Question

Find the value of a. A: 15, B: 19

Answer 1

A: 15

Explanation:

The angles are opposite to each other.

Vertically opposite angles are equal in size.

Put up an equation and solve for a.

6a + 10 = 3a + 55

Subtract 3a and 10 on both sides.

6a - 3a = 55 - 10

Combining like terms.

3a = 45

Divide both sides by 3.

a = 45/3

a = 15

The value of a is 15.

Answer 2

a = 15

Explanation:

=> 6a + 10 = 3a + 55 (Vertically Opposite Angles are congruent)

Combining like terms

=> 6a - 3a = 55 - 10

=> 3a = 45

Dividing both sides by 3

=> a = 15