The radius of a circle is 4 kilometers. What is the area of a sector bounded by a 45° arc?

Abird on top of a 200 ft bridge tower sees a man standing on the lower part of the bridge (which is 50 ft above the ground). the angle of depression from the bird is 26 ̊. how far is the man from the base of the bridge tower? with explanation and pictures .

Cos^2x+cos^2(120°+x)+cos^2(120°-x)i need this asap. pls me

How many quarts of a 50% solution of acid must be added to 20 quarts of a 20% solution of acid in order to get a 40% solution of acid?