Tag: right triangles

Proofs of angle in a semicircle theorem

The Angle in a Semicircle Theorem states that the angle subtended by a diameter of a circle at the circumference is a right angle. An alternative statement of the theorem is the angle inscribed in a semicircle is a right angle. Proof Draw a radius of the circle from C. This makes two isosceles triangles.

Area of an Equilateral Triangle

Somebody left this in my message box: Problem If a triangle is an equilateral triangle with 3m and you are not given the perpendicular length of a triangle, how do you calculate the area of a triangle? Obviously the sender know that the perpendicular length aka height or altitude of the triangle is needed to