4. An arch is to be constructed so that its shape follows the curve y=- 1/2 x^2+10x wier horizontal distance along the ground and y measures the vertical height of the arch above t units of feet. The general graph of this arch is shown below. (a) Based on this equation, what is the height of the arch at the turning point? Show the work that leads to your answer. y (b) If a second arch was to be created that had the same height, but only half the width, determine an equation for this arch based on our work in this lesson. (c) Choosing an appropriate graphing window based on (a), graph the second ard your graphing window. Use your calculator to determine the new turning po