DDD, E E\,E and F F\,F are points on the circumference of a circle, centre OOO. DE DE\,DE is a diameter.
Angle FDE=(4x+10)∘FDE = (4x + 10)^\circFDE=(4x+10)∘ Angle DEF=x∘DEF = x^\circDEF=x∘
Find the value of xxx.
You must show all your working.
