You can model the arch of the fireplace using the equation y =-1/9(x+18)(x-18) when x and y are measured in inches .the x-axis represents the floor .find the width of the arch at floor level

first, you divide the triangle in two, tô form a retangle triangle. after, using pythagoream theorem:

18^2 = 14^2 + (x/2)^2

(x^2/4) + 196 = 324

x^2/4 = 324 - 196

x^2/4 = 128

x^2 = 512

x = √512

x = √2^9

x = 16√2 cm

i hope i you.

lol   i know im kinda tired too