Symmetry of a semicircle

What is the line of symmetry of a semi-circle? Does it have rotational symmetry?

Let XY be the diameter of a semicircle with centre O. Let A be a variable point on the semicircle and B another point on the semicircle such that AB is parallel to XY. The value of angleBOY for which the inradius of triangle AOB is maximum, is

If the perimeter of a semicircle is 18 cm, what will be its diameter ?

Find the perimeter of a semicircle of radius 7 cm.

Symmetry of a circle.

Symmetry of a square

What is the measure of a semicircle ?

Area: circumference and perimeter of semicircle