a. I'm guessing it means ec not eh as the arc
efc= (db-ec)/2
efc=135-25=110/2= 55°
b. de=25 ef=5 cf=6 cb=?
formula (de+ef)×ef=(cb+cf)×cf
plug in
(25+5)5=(x+6)6
125+25=6x+36
150=6x+36
-36 both sides
114=6x
÷6 both sides
x=9
cb=9
c. df=de+ef
25+5=30
d. fb=cf+cb
6+9=15
