The mathematical relationship between the distances and angles for this triangle involve trigonometry, we need to use the trigonometric "sine" function. In particular, sine of angle e = of X = (sine of e) (1 AU) = sin(@) AU So, X, the distance between the Sun and Venus in AU, is just the sine of the elongation angle when Venus appears half lit. Use your calculator (make sure it is set for degrees, not radians) to compute this value or type "sine of 45.8 degrees" into Google - but use y 0 angle from the earlier table. Venus to Sun Distance = AU