find the measure of a line EC

9514 1404 393
Answer:
41
Step-by-step explanation:
The product of segment lengths from the point of intersection to the circle is the same for both chords.
QC·QE = QD·QF
2x(21) = (x+4)(30)
14x = 10(x +4) . . . . . divide by 3
4x = 40 . . . . . . . . . . subtract 10x
x = 10 . . . . . . . . . . . .divide by 4
2x +21 = EC = 2(10) +21 . . . . . find EC
EC = 41