# maths

posted by
**Anonymous**
.

L and m are two parallel tangents at A and B. The tangent at C makes an intercept DE between L and m. Prove that angle DEF = 90 degree.

posted by
**Anonymous**
.

L and m are two parallel tangents at A and B. The tangent at C makes an intercept DE between L and m. Prove that angle DEF = 90 degree.