Given:
b1 = 17 ft
b2 = 20 ft
h = 13 ft
r = 17/2 = 8.5 ft
Area of the Semi-circle = 1/2 π r²
= 1/2 (22/7) (8.5²)
= (11/7) (72.25)
= 113.535 ft²
Area of the trapezium = (h) (b1 + b2) / 2
= (13)(17 + 20)/2
= 240.5 ft²
Total area of the amphitheater stage = Area of Semi-circle + Area of the trazezium = 113.535 + 240.5 = 354.035 ft²
