Question

Given: mORP = 80°

mORN = (3x + 10)°
Prove: x = 30

Which statement could be used in step 2 when proving x = 30?

A. ORP and ORN are a linear pair
B. ORP and ORN are vertical angles
C. 80 = 3x +10
D. x = 30

Answer 1

The Correct answer would be A.

Answer 2

we know that
A linear pair is a pair of adjacent angles formed when two lines intersect.
The two angles of a linear pair are always supplementary , which means their measures add up to 180°
so
ORP and ORN are a linear pair
mORP+ mORN = 180°
80°+ (3x + 10)°=180°
3x=180°-90°
x=90°/3
x=30°

therefore

the answer is the option
A. ORP and ORN are a linear pair