Question

In the circle above, Line EF and CD intersect at G. Determine the measure of arc DE.

Answer 1

Answer:

100

Step-by-step explanation:

It is a rule that for two opposite arcs, with intersecting lines, between them, the average of the arcs is equivalent to the inside angle. Given this, we can say that:

(CF + ED)/2 = angle G

plug values in

(12x+9x+10)/2 = 110

multiply both sides by 2

21x + 10 = 220

subtract 10 from both sides

21x = 210

divide both sides by 21

x=10

Plug this into DE

10*9+10 = 100