A tunnel has an opening that is half an ellipse. The tunnel is 120 ft long and 30 ft high. How high is the tunnel 10 ft from the right edge?

Question

Please answer in inches, I appreciate it!

Answer 1

x^2/60^2 + y^2/30^2 = 1

50^2/3600 + y^2/900= 1 (use 50 for x, as 60-10=50)

y^2/900 = 1 - 2500/3600 = 1 -25/36

y^2 = 900 - 100(25)/4 = 900-625 = 275, use only the positive square root as it's the top half of an ellipse

y = sqr275 = about 16.58 feet high