Answer:
x = 80°
Step-by-step explanation:
To find x, we need to create an equation.
Recall that the sum of all the 4 interior angles of a quadrilateral = 360°.
<em>Therefore:</em>
m<B + m<A + m<C + m<P = 360°
m<B = 20° (given)
m<C = 20° (given)
m<A = ½*x = x/2 (inscribed angle theorem)
m<P = (360 - x)°
<em>Plug in the values and solve for x</em>
<em>Collect like terms</em>
<em>Subtract 400 from each side </em>
<em>Multiply both sides by 2</em>
<em>Divide both sides by -1</em>