The Correct Answer to this would be 100%:

Option “85.4”.

(Work Below)

Given:

height = 6m

chord = 20 m

We need to find the radius of the circle.

20 m = 2 √ [ 6m( 2 x radius – 6 m ) ]

20 m / 2 = 2 √[ 6m( 2 x radius – 6 m ) ] / 2

10 m = √ [ 6m( 2 x radius – 6 m ) ]

(10 m)² = √[ 6m( 2 x radius – 6 m ) ] ²

100 m² = 6 m( 2 x radius – 6 m )

100 m² = 12 m x radius – 36 sq m

100 m² + 36 m² = 12 m x radius – 36 m² + 36 m²

136 m² = 12 m x radius

136 m² / 12 m = 12 m x radius / 12 m

11.333 m = radius

the area beneath an arc:

Area = r² x arc cosine [ ( r – h ) / r ] – ( r – h ) x √( 2 x r x h – h² ).

r² = (11.333 m)² = 128.444 m²

r – h= 11.333 m – 6 m = 5.333 m

r * h = 11.333 m x 6 m = 68 m²

Area = 128.444 m² x arc cosine [ 5.333 m / 11.333 m ] – 5.333 m x √[ 2 x 68 m² – 36 m² ]

Area = 128.444 m² x arc cosine [ 0.4706 ] – 5.333 m x √ [ 100m² ]

Area = 128.444 m² x 1.0808 radians – 5.333 m x 10 m

Area = 138.828 m² – 53.333 m²

Area = 85.4 m²

Hope this Helps! Have A Wonderful Day! 🙂

And as Always…