Step-by-step explanation:
draw a Doameter and the measurement of the staright line is 180
then we have 60 radius
Diameter=2r
Diameter=2×60
Diameter=120
if the circle is semicircle the arc will be 180
the diameter cut the circle in two part or semicircle
to proof the arc is 180° we can add the two semicircle and 180°+180°=360°
the arc will be 180°
