Which angle is an exterior angle of the triangle?

If t17 = 3 (t5) in an arithmetic progression, find t1 in terms of d.

Abicycle training wheel has a radius of 3 inches. the bicycle wheel has a radius of 10 inches. approximately how much smaller, in square inches and rounded to the nearest hundredth, is the area of the training wheel than the area of the regular wheel? *

The longer leg of a 30-60-90 trangle is 18