mat116
posted by thawk on .
In a triangle ABC, angle B is 4 times angle A and angle C is 16 degrees less than 5 times angle A.
What is the size of angle A _____
B _____ and C _____
I would like to learn this so please be so kind to walk me through the steps. I appreciate you very much!!!

make a diagram, it does not have to be to scale.
let angle A = x
(I picked A since both conditions stated used it as a reference)
"angle B is 4 times angle A" > angle B = 4x
"angle C is 16 degrees less than 5 times angle A" >angle C = 5x  16
Now, what do you know about the 3 angles of a triangle?
Don't they add up to 180° ?
so x + 4x + 5x16 = 180
10x = 196
x = 19.6°
So by the definitions above
A = 19.6
B = 78.4
C = 82
(check for their sum)