Question

In circle A shown below, m is 71° and m is 78°.
What is m∡FDE?

http://learn.flvs.net/webdav/assessment_images/educator_geometry_v14/pool_Geom_3641_0801_03/image0044e847a03.gif

Answer 1

I really need an explanation.. not just an answer.

Answer 2

Join FA, AE, CE, AB and AC.
Angle FAE = 78
angle BAC = 71
angle FCE = 1/2 (angle FAE) = 1/2 (78) = ... (angle at centre, twice angle at circumference)
angle BEC = 1/2 (angle BAC ) = 1/2 (71) = ... (angle at centre, twice angle at circumference)

Angle FDE = angle FCE + angle BEC = ... (ext. angle of triangle)

Answer 3

So 74.5?

Answer 4

That's what I've got :|

Answer 5

Awsome that's right(: Thanks.

Answer 6

Welcome. I hope my workings make sense to you :|