Question

Find the size of the angle marked a

Answer 1

• 57°.

Explanation:

What we know is:

• One angle is 123°.

We don't know:

• angle a°.

So, we add both angles up to 180°:

• 123 + a = 180.

Lets solve 180 - 123:

• 180 - 123
• = 57
• a° = 57°.

Angle a° is 57°.

Answer 2

57°

Explanation:

Given line is straight line

then whole angle is 180°

then 180 - 123 = a = 57