Answer:
Idk if you have to solve it by X so I say it's X=2.125
You can revise: the sum of the two adjacent angles is 180°
and the sum of the measurements of the three corners in a triangle is also 180°
<1= 180°-57°=123°
As <2=52°, so we have <3= 180°-(28°+71°+52°)= 180°-151°=29°
have fun
To calculate it use pythagoras: a^2+b^2=c^2
7^2+10^2=49+100=149
calculate the square root:

so the diagonal is about 12.2 inches long
It's diameter is 17.98. (I'm pretty sure I'm right I even used a calculator, if not sorry)