Math Is Fun Forum

Hannibal lecter

Member

Registered: 2016-02-11

Posts: 392

Pairs of angel

I was study that the some of angels of a triangle contain 180 degree
my problem is with the proof

please see this photo I marked up the angle by sky blue color it's 125 degree

now this is another photo figure about the triangle

 

now how could that angel which is 125 degree equal angel F?

by just looking it, it's look like B+C which is 125 degree
so F can't be 125 degree

I combined the two figures into one using pen and paper and see the photo :-

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Wisdom is a tree which grows in the heart and fruits on the tongue

Bob

Administrator

Registered: 2010-06-20

Posts: 10,181

Re: Pairs of angel

The two diagrams are for completely different angle problems so they cannot be combined like this.

In the second one there are lots of equal angles:

A = E
C = F
B + C = D
A + B = G

You can use these answers as follows:

180 = A + B + C = E + B + F

So the angles of a triangle add up to 180.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob