Question

Line HF is tangent to circle D at point E. SEgment DE is the radius of circle D, what is true about DEF?

Answer 1

D.angle def is an obtuse angle

Answer 2

When we draw a circle with the centre at D and have a tangent HF to the circle D at point E, the angle DEF will be a right angle.

In other words angle DEF = 90 degrees

Since HF, the tangent, is a straight line, the other angle DEH should also be = 90 degrees because the straight line has an angle of 180 degrees

Therefore angle DEF = angle DEH = 90 degrees

Therefore, angle DEF is congruent to angle DEH (Option A)