Answer:
x = 16 , MJ ≈ 8.1
Explanation:
5
the inscribed angle JKL is half the measure of the arc JL that subtends it, so
9x = 2 × 72 = 144 ( divide both sides by 9 )
x = 16
6
the angle between tangent KJ and diameter JL at the point of contact is right, that is ∠ KJL = 90°
then Δ KJL is a right triangle
using Pythagoras' identity in the right triangle
KJ² + JL² = KL²
10² + JL² = 19²
100 + JL² = 361 ( subtract 100 from both sides )
JL² = 261 ( take square root of both sides )
JL =

MJ is the radius of the circle and is half the diameter JL
MJ =
÷ 2 ≈ 8.1 ( to 1 decimal place )