Answer:
66°
Explanation:
When a radius(diameter in this case) is perpendicular to a chord, it bisects the chord and the arc formed by the chord. Because of this, we can say mHJ is equal to mKJ. We can write an equation:
mHJ = mKJ
and substitute:
x + 20 = 6x - 45
20 = 5x - 45
65 = 5x
x = 13
mHK is the sum of mHJ and mKJ, we can write mHK as the expression:
x + 20 + 6x - 45
7x - 25
We can substitute x:
7(13) - 25
91 - 25
66°