Question

One angle of a triangle is 20 degrees. The second angle's measurement is four times the third. What is the measure of the third angle?

Answer 1

The angles are
`A=20^@`
`B=128^@`
`C=32^@`

Explanation:

Let A,B, and C be the angles in a triangle
`A=20^@`
`B=4C`
Sum of angles in a triangle is 180
`A+B+C=180^@`
`20^@+4C+C=180^@`
`20^@+5C=180^@`
`5C=180^@-20^@`
`5C=160^@`
`C=160^@/5`
`C=32^@`
`B=4xx32^@`
`B=128^@`
Check
`A+B+C=20^@+128^@+32^@`
`20^@+128^@+32^@=180^@`
Thus
`A+B+C=180^@`
The angles are
`A=20^@`
`B=128^@`
`C=32^@`