Answer:
see explanation
Explanation:
The sum of the 3 angles in a triangle = 180°
In each question sum the 3 angles and equate to 180
3
a.
x + 8x + 90 = 180
9x + 90 = 180 ( subtract 90 from both sides )
9x = 90 ( divide both sides by 9 )
x = 10
b
4x - 5 + 3x + 11 + 90 = 180
7x + 96 = 180 ( subtract 96 from both sides )
7x = 84 ( divide both sides by 7 )
x = 12
4.
4x + 2x + 11 + 19 = 180
6x + 30 = 180 ( subtract 30 from both sides )
6x = 150 ( divide both sides by 6 )
x = 25
5.
5x + 20 + 2x - 5 + 3x - 10 = 180
10x + 5 = 180 ( subtract 5 from both sides )
10x = 175 ( divide both sides by 10 )
x = 17.5