Question

Angle inscribed in a semicircle is a right angle Theorem

Answer 1

here, angel ABC is inscribed in the semicircular arc AXC.
the measure of semicircular arc is 180'. .....(1)
hence, m of angle ABC =1/2(m arc AXC)
.
. . ABC =1/2x180'
ABC=90'.............(2) [by inscribed angle theorem ]
.
. .from 1 and 2
angle inscribed in a semicircle is 90'.