Year 5 really impressed me with their superb knowledge on angles! Can you work out these unknown angles using your knowledge of different angles rules? (Don't forget to include great mathematical vocabulary in your explanation such as 'angles on a line', 'angles in a triangle'!)

B is 60 because the angle is on the line and has to add up to 180 and the other angle is 120 so 120+60=180.This now means a is 60 because it is a equal side so its has to be a equal angle. I now know that d is 120 because the angle is on a straight line so it has to be 180. C is 120 because a+b=120 and because its a triangle it has to add up to 180.

ReplyDeleteSome excellent reasoning there Sam! Check your answer for C, 120 + 120 would equal 240!

DeleteYes it would Mr Troy you are not wronge but if you are stuck you could do 100 add 100 which is 200 then 20 add 20 which is 40 and 0 add 0

DeleteAdd them together 200+40=240

A=60 degrees

ReplyDeleteB=60 degrees

Because angle B plus 120 degrees must equal 180 because it is a straight line.

A=B because its a isosceles triangle.

C=60 because the angles in a triangle add up to 180.

D=120 because A plus D is 180.

E=30 because D plus 30 degrees is 150.180 - 150 = 30 degrees.

a = 60 degrees

ReplyDeleteb = 60 degrees

c = 60 degrees

d = 120 degrees

e = 30 degrees

Angles on a straight line add up to 180 degrees so b = 180 - 120 = 60

In a triangle angles opposite to equal sides are equal so a is 60 degrees.

The sum of all the angles in a triangle is 180 degrees so c must be 60 degrees as well. If a is 60 degrees then d would be 120 degrees because angles on a straight line always add up to 180 degrees. 120 + 30 = 150 so e must be 30 degrees.

Karishma, I never knew that you were in Mr Troys group.

DeleteB is 60 degrees because there are two joint angles on that line;120 degrees, and B. Whenever there are angles on a line,the angles must always equal 180 degrees when you add them together, and that's why B is 60 degrees.

ReplyDeleteA and C are also 60 degrees because, first of all, A,B and C are in an isosceles triangle, and I know that because there are two small lines poking out from the top two sides of that triangle, and whenever those lines are there, that means that they are the same length as another side, and because an isosceles triangle has two equal sides, that proves that A,B and C are in an isosceles triangle.Second of all, whenever there are angles in an isosceles triangle, they will always be equal to each other, and since B is 60 degrees and is in an isosceles triangle, that makes A and C 60 degrees as well.

D is 120 degrees because it is on a line with angle A, and since angle A is 60 degrees, D has to be 120 degrees because 60 add 120 equals 180 degrees, and on a line with two angles on it, the rule is the angles must add up to 180 degrees.

E is 30 degrees because in the triangle D and E are in, two angles have been found.The first angle was there already and it is 30 degrees, and I've already found what angle D is, and that's 120. 30 degrees add 120 degrees equals 150 degrees and that means there's only 30 degrees left until you can make 180.

What an amazing explanantion Kamille! You have used some amazing mathematical vocabulary there!

DeleteYes Mr Troy. My one is very messy but I think is correct. I felt it was easy but I had to think about it in the same time. Thanks for giving us extra maths classes

DeleteSeemontini

A:60 degrees

ReplyDeleteB:60 degrees

C:60 degrees

D:120 degrees

E:30 degrees

First of all to find out A you do 180 degrees-120 degrees=60 degrees because A and B are the same so A and B are 60 degrees.

Next to find out C you do 60 degrees+60 degrees=120 degrees as A and B are 60 degrees each then you subtract 120 degrees from 180 degrees which is 60 degrees and you've found out what C is.

After,to work out D you do 180 degrees-A which is 120 degrees and that's what D is.

Finally to work out E you do D+30 degrees=150 degrees and minus it from 180 degrees to get 30 degrees and that's you answer.

B is 60 degrees because the angle next to it is 120 degrees and 120 degrees + 60 degrees = 180 degrees. Angles on a straigt line always add up to 180 degrees.

ReplyDeleteA is also 60 degrees because the triangle is an isosceles triangle. An isosceles triangle has always got two angles that are the same. The two angles that are the same are angle A and B.

C must be 60 degrees too because it is in the same triangle as A and B. All three angles have to add up to 180 degrees and if A and B together are120 degrees , angle C must be 60 degrees aswell.

Angle D is 120 degrees because the other angle (A) is 60 degrees and both are on a straight line.

E is 30 degrees because, as explained above, all three angles in a triangle need to add up to 180 degrees.

If you look at 120 degrees and b they are an angles on a line, so they have to add add up to 180 degrees,the same as a and b.

ReplyDeleteb=60 180

-120=60

A,b and c are in an isoceles triangle because there are two small line on the sides showing they are the same length,so two of the angles have to be the same. It is a angles in a triangle so it must add up to 180 degrees.

a=60

c=60 180

-120=60

A and d are angles on a line so if a is 60 dgrees d must be:

d=60 180

- 60=60

D,e and 30 degrees are in a scalene triangle so all the angles have to be different.

e=90 30 180

+60[d]=90 - 90=90

B is 60 because it is next to the line of 120 degrees. We know it is an isosceles triangle because of the 2 little lines on the triangle. So a is the same to find out c 60 add 60 = 120 and I know a triangle equals to 180. So I do180-120=60. So c is 60. D=120 because a is 60.And 120 +60=180. E= the sum of 120+30=150 and 150-180= 30. So e is 30.

ReplyDeleteB=60 because sum of angles on a straight line equals to 180 degrees and if one angle is 120, the other would be 180-120=60

ReplyDeleteA=60 because it is an isosceles triangle with side BC=AC therefore angle A will be equal to angle B.

C=60 because in a triangle all the internal angles add up to 180 degrees therefore angle C= 180-(60+60) =60.

D=120 because if angle A equals to 60 and sum of angles on a straight line is 180 degrees therefore angle D=180- 60=120.

E=30 because sum of internal angles of a triangle equals 180 therefore angle E=180-(120+30)=30

Please note:

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Since angles A, B and C are all 60 degrees therefore that triangle should be an equilateral triangle and not an isosceles.

Also since 2 angles in the other triangle are same (30 degrees) therefore that triangle should be an isosceles triangle and not scalene.

I hundred per cent agree with you Yana. That's why I didn't do the homework straight away.

DeleteSanjuka and Yana well spotted! This did make the question look very odd indeed! If the traingle is equilateral (which the angles state it is!) What should that say about the sides as well? (Which it doesn't appear to!)

DeleteDoes the sides of a,b,and c all should have the little line to show it is equal. Also d and e triangle should have two lines on their triangle because e is 30 degrees so it is a isosceles.

DeleteSpot on!

ReplyDeleteB 60 D 120

ReplyDeletee 30

F 180

a 60 oNE OF THE TRIANGLES THAT LOOK ISCOSCILIS IS EQUAL

C 60

I had tot think about the trick triangle but then I found it out

ReplyDeleteAngle Geometry

ReplyDeleteA=60 because A is the same as B and the 2 lines are equal which means the angles are equal.

B=60 because the angle next to it is 120 and angles on a straight line have to add up to 180.

C=60 because the other 2 angles are 60 and angles in a triangle have to add up to 180.

D=120 because A is 60 and angles on a straight line have to add up to 180.

E= 30 because D is 120 and the other angle is 30 and angles in a triangle have to add up to 180.By Joshua 5JM

B=60 as it is on a straight line and the other angle is 120. So it would be 180-120=60

ReplyDeleteA=90 as it is on the same line as D , which looks a bit like 90.

So D=90

A+B=150. THAT MEANS C=(180-150)=30

if D and the other angle=120,E=(180-120)=60.