Question

What is the value of x

Answer 1

180 - 100 = 80

so

x + 70 + 80 = 180

x + 150 = 180

x = 30

Answer

B. 30

Answer 2

Hey!

The sum of all 3 angles in a triangle always adds up to 180°. One of the angles is 70°. Another angle is 80° because 180 - 100 = 80. Add the 2 angles and subtract it from 180.

$70 + 80 = 150$

The sum of the 2 angles is 150°. Subtract that from 180

$180 - 150 = 30$

That means x is equal to 30

$\framebox{Answer = 30 \° = B}$.