Answer:
x = 16°
Explanation:
What we know:
∠JML = 47°
∠JKL = (7x + 21)°
∠JML is an inscribed angle
∠JKL is an inscribed angle
Inscribed angles are half of the value of their intercepted arc
So if m∠JML = 47° then mArc JL is double that or 94°
And ∠JKL is intercepted by Arc JML which is the rest of the circle not intercepted by ∠JML so
mArc JL + Arc JML = 360°
94 + Arc JML = 360
Subtract 94 from both sides to isolate Arc JML
Arc JML = 266°
So if Arc JML = 266° then it's intercepted inscribed angle is half of that.
Arc JML ÷ 2 = ∠JKL
266 ÷ 2 = ∠JKL
133 °= ∠JKL
Now we can use this value and set it equal to the expression to find the value of x
(7x + 21) = 133
Subtract 21 from both sides to isolate the x
7x = 112
Divide both sides by 7
x = 16