Prove the property of a leg of a right-angled triangle equal to half of the hypotenuse.

Given:
right-angled triangle ABC,
angle A = 90 degrees,
angle B = 30 degrees,
Prove that AC = 1/2 * BC.
Proof:
Consider a right-angled triangle ABC.
The sine of the angle is equal to the ratio of the opposite leg to the hypotenuse. Consequently
sin of angle B = AC / BC;
AC = sin of angle B * BC;
AC = sin angle 30 * BC;
AC = 1/2 * BC.
This means that the leg lying opposite an angle of 30 degrees is equal to half of the hypotenuse. Q.E.D.