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In given figure

White ball point forms one large right angled triangle with top cushion.

White ball point forms one small right angled triangle with top cushion.

Angle of large and small right angled triangles is same ( indicated in given figure )

For large right angled triangle

Let Adjacent = x

Opposite = 3 ft

Sin Θ = 3 / x

For small right angled triangle

Adjacent = 5 - x

Opposite = 1.8 ft

Sin Θ = 1.8 / 5 – x

3 / x  = 1.8 / 5 – x

3 ( 5 – x ) = 1.8 x

15 – 3x = 1.8 x

1.8x = 15

x = 15 / 4.8

x = 3.125 ft

White ball touches at the top cushion from left side is = 1 + x

= 3.125 + 1

= 4.125 ft

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The white ball should hit the top cushion 4.125 ft from the upper left corner.