Question

1.) What is m ABC?
Show your work.
75
135
с

Answer 1

`\angle ABC =60`

Explanation:

Given

`\angle CAB = 75`

The attached triangle

Required

Find
`\angle ABC`

First, calculate
`\angle BCA`

`\angle BCA + 135 = 180` --- angle on a straight line

`\angle BCA = 180 - 135`

`\angle BCA = 45`

`\angle ABC` is then calculated using:

`\angle ABC + \angle BCA + \angle CAB =180` -- angle in a triangle

`\angle ABC + 45+ 75=180`

`\angle ABC =- 45- 75+180`

`\angle ABC =60`