Allison is making a pennant flag for her middle school. She plans to make the flag as shown below. A triangular flag pennant with a base of 12 inches and height of 28 inches.
Part A: How much material, in square inches, will Allison need to make the flag? Show all work.

Part B: Allison decides to double the base and double the height of the flag. Will this double the area? Explain.

Part C: She then decides to make the height of the flag 40 inches and the area of the flag 360 square inches. What will be the measure of the flag's base? Show all work.