Answer:
radius = 9.5 cm
Step-by-step explanation:
If 2 chords intersect then the product of the parts of 1 chord is equal to the product of the parts of the other chord, that is
PT × TQ = ST × TR
PT × 3 = 4 × 12 = 48
3 PT = 48 ( divide both sides by 3 )
PT = 16
then
diameter = PT + TQ = 16 + 3 = 19 cm
radius = 19 ÷ 2 = 9.5 cm
