Another set of calculations for WP2 returns:
d = .002862984
h2 = b – 87.76617538 + d cos 39.80557° = 39.87466173 = 39.87466173
( y2 = 87.78133797)
x2 = –117.4309386 + d sin 39.80557° = –117.4291058
Re-evaluating the ellipse semi-axes:
b = 127.6559997 , a = 161.7364819
Ellipse slope equals 10/12 at ... (–117.4263848, 87.7836055)
The co-ordinates of WP2 and the point on the ellipse where the slope equals
the 10/12 slope of the rafter now agree to two decimal places.
Supplementary
