Answer:
180°
Step-by-step explanation:
The measure of an inscribed angle (inscribed inside a circle) is half the measure of its inscribed arc.
m∡H = (1/2)(m arc GJI)
m∡J = (1/2)(m arc GHI)
m∡H + m∡J = (1/2)(m arc GJI + m arc GHI)
But those two arcs added together on the right side are the whole circle, so they add to 360°.
m∡H + m∡J = (1/2)360°
m∡H + m∡J = 180°
