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Calculate the area of a parallelogram by multiplying base by height, illustrated with an example using base 25 and height 12 to obtain 300 cm².

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

Explore the area of trapezium by identifying the two bases a and b and the height, with an example that yields an area of 15.

Calculate the area of an obtuse triangle using area equals base times height, even when the angle exceeds 90 degrees, illustrated with an example where the angle is 100 degrees.

Compute the area of a scalene triangle with Heron's formula by finding the semiperimeter x = (a+b+c)/2 and using sqrt(x(x-a)(x-b)(x-c)), shown with sides 11, 13, 16 giving about 7.99 cm².

Explore the circumference and area of a circle using its radius, and follow a worked example with a 3 cm radius to practice computing both measurements.

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 exterior angle theorem in geometry, showing how the exterior angle equals the sum of the interior angles, illustrated with a solved example using 71°, 66°, and 137°.

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.

Apply the isosceles triangle theorem to find angles: equal base angles, the third angle equals 180 minus twice the base angle, illustrated with a concrete example.

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.

Apply the pyramid volume formula by calculating one third of the base area times height, and verify with a 3 by 4 base and 4 height example yielding 16.

Calculate the volume of a rectangular prism by multiplying length, width, and height; the example shows 2 times 6 times 4 equals 48.

Learn how to find the volume of a triangular prism by using the base area (half the rectangle) and the height. See an example calculation to apply the method.

Explore how to calculate the surface area of a rectangular prism using its length, width, and height, with a step-by-step example.

Learn geometry now explains surface area of a coin modeled as a cylinder with circular bases, showing how radius and slant height determine base and lateral areas in the formula.

Calculate the surface area of a cube by six equal square faces with side length a, giving six times a^2 as the total; an example shows 24 cm^2.

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

Explore the surface area of a sphere, a three-dimensional shape, using its radius and the surface area formula, with an example using a 2 cm radius.

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.

Compute the surface area of a regular tetrahedron using sqrt(3) times a^2, with examples for a = 6 cm and a = 8 cm.