accompanying worksheets. a. 1536 square meters b. MathBitsNotebook.com | MathBits' Teacher Resources Now this looks like an interesting problem. Since the sum of the interior angles of a triangle is 180, then the central angle, angle AOB, must be 180 - 100, or 80 degrees. What other information is needed in order to prove the triangles congruent using the SAS Congruence Postulate? EF*tan(30) = DE . Next lesson. If AC = 24, and m