Learn Geometry Now!

Compute the area of an isosceles triangle using base and height, illustrated by a base of six and a height of eight.

Compute the area of a circle segment using radius and central angle, via area = (theta/360) pi r^2 − (1/2) r^2 sin theta, with r=2 and theta=90 degrees.

Learn the alternate segment theorem, which relates the angle between a tangent, a circle, and a triangle, to the opposite angle in the triangle, with practical example calculations.

Explore how cyclic quadrilaterals inside a circle relate angles so that certain angle pairs sum to 180 degrees, and learn to find alpha, beta, and gamma using straight-line angle sums.

Explore the inscribed angle theorem in circles, showing that the central angle equals two times any inscribed angle, with alpha, beta, and gamma as examples.

Learn the triangle proportionality theorem by using a parallel line in a triangle to set up proportions and solve for x in a worked example.

Learn to compute the volume of a cube using the side length, where volume equals side length cubed, with a 2 cm example yielding 8 cubic centimeters.

Explains the volume of a cylinder by multiplying the base area π r^2 by the height, and shows a sample calculation using π ≈ 3.14.

Compute the cylinder's surface area by summing two circular bases and the rectangular side, with radius 4 cm and height 5 cm.

learn how to calculate the surface area of a square-based pyramid by combining base and lateral areas, with a worked example and unit considerations in meters or centimeters.