Answer:
x = 7
Step-by-step explanation:
3x - 9 = 12
3x = 12 + 9
3x = 21
x = 21 ÷ 3
x = 7
See the attached picture:
The value of x is 30
<u><em>Solution:</em></u>
Given that measure of exterior angle of regular polygon is 2x
The measure of interior angle is 4x
To find: value of x
The sum of an interior angle plus an exterior angle must be equal to 180 degrees (supplementary angles)
measure of exterior angle + measure of interior angle = 180
2x + 4x = 180
6x = 180
x = 30
<em><u>Finding the measure of an exterior angle</u></em>
measure of exterior angle = 2x = 2(30) = 60 degrees
<em><u>Finding the measure of interior angle</u></em>
measure of interior angle = 4x = 4(30) = 120 degrees