Draw any triangle, measure each angle, and find the sum. Repeat with other triangles. What seems to be the sum? Informal Statement: The sum of the three angles of a triangle is equal to one straight angle.

What is the sum of the geometric series in which a1 = 7, r = 3, and an = 1,701? hint: cap s sub n equals start fraction a sub one left parenthesis one minus r to the power of n end power right parenthesis over one minus r end fraction comma r ≠ 1, where a1 is the first term and r is the common ratio