Imagine two line segments where each represents a slant height of the cone. the segments are on opposite sides of the cone and meet at the apex. find the measurement of the angle formed between the line segments.

Imagine that we cut the cone in half with a vertical plane. In this plane we'd see points a, b and c. We need to find the measure of angle bca, and then double that angle, to obtain the answer to this problem.

Note that tan (angle bca) = opp / adj = 2 / 6, or 1/3, or 0.333...

Working backwards to find angle bca, we use the inverse tangent function:

arctan 0.3333.. = approx. 0.322 radians, or 18.435 degrees.

Doubling that gives us the measurement of the angle formed between the line segments: 2(18.435 deg) = 36.9 degrees, approximately.