so in math we have to do doubled but i don't know how to and my teacher wont answer my question so like can somebody help me find what doubled is?

Grace is standing 18 feet from a lighthouse and kelly is standing 10 feet from grace. the angle that grace looks up to see the top of the lighthouse is 45°. the angle that kelly looks up to see the top of the lighthouse is y°. find the height, h, of the lighthouse. find the angle, rounded to the nearest tenth of a degree, in which kelly looks up to the top of the lighthouse. to the nearest tenth of a degree, find the value of x° . in two or more sentences, explain your calculations

What is the surface area of a cube with the volume of 729 ft?

Which expression represents the total perimeter of her sandwich, and if x = 1.2, what is the approximate length of the crust?