Question

Two angles in a triangle are have the same measurement. The third angle is 12 degrees less than

the first angle. What are the measurements of angle 1, 2 and 3? (hint: you will need to know
how many degrees are in an triangle)

Answer 1

There are 180 degrees in a triangle and if two of them are the same we can call them both a:

a + a + b = 180
2a + b = 180

Next, b is 12 degrees less than a so:
a - 12 = b

2a + a - 12 = 180
3a - 12 = 180

Add 12 to both sides
3a = 192

Find a:
a = 192 / 3
a = 64

This means angle 1 and angle 2 are equal to 64 degrees and angle 3 is 52 degrees

To check:
64 + 64 + 52 = 180 degrees