Question

Architectural Designers is creating a schematic for a bridge over the Columbia River whose arch is in the shape of a parabola. The road, 40 feet above the river surface, represents the directrix of the parabolic arch. The focus of the parabolic arch is located 20 feet above the river surface. In the schematic, the river surface will be positioned along the x-axis and the axis of symmetry for the downward opening parabolic arch will be positioned along the y-axis. Which equation best models the parabolic arch in the schematic?

Answer 1

Answer:c

Explanation:

A and D are incorrect just by the fact that they dont open downward(arch) B. Is also incorrect because the y intercept 10 doesn’t include the focus point 20 also u can use this calculator called parabola calculator to pin point focus and directive just in case u want to check my answer. C is most correct because it has intercept 30 including focus point 20...(SHOUT OUT TO ILT)