Can you help me on this step by step willing to give you 30 points

Evaluate cos2θ for cosθ = square root of 3/2

What is r i 4.5+10r=-6.5 with work pls

Sherrie is baking a pie for her family. she leaves the room and comes back to 35% of the pie having been eaten before she can put the topping on. how much 1 square inch strips of dough will she need for the top, now that a portion is missing? round your answer to the nearest while nimber.