My friend and i need : a/4 - 5/6 = 1/2

Acommunity group is building a garden on a rectangular lot of land. the lot measures 5x by 10x and the garden will be circular with a radius of 3x. how much of the land will be left over after the garden is built? a. 41 pi x^2 b. x^2 (50 - 9 pi) c. x^2 (50 - 3 pi) d. 41x^2

Need with this question with all work shown

Find the exact value of sin 3.14/12