Answer:
x = 11
Step-by-step explanation:
In ΔSTU ,
m∠S = (11x+3)° ; m∠T = (2x+16)° ; m∠U = (x+7)°
According to angle sum property of a triangle , sum of all the interior angles of the triangle is 180°.
So,




pi·18.6^2·123°/360° - 1/2·18.6^2·SIN(123°) = 226.3
Just multiply 3 1/3 x 1 1/4 which is 3 and 7/12 miles well together 3 , 7/12