Area of rectangles, triangles, parallelograms and ellipses.
Free to use, no sign-up required. Area of Shapes is one of 198 tools built into Xenition, alongside a chat that can use them for you.
Finds the area of a rectangle, triangle, ellipse or parallelogram from two measurements, and draws the shape to scale.
Rectangle = width × height. Parallelogram = base × height. Triangle = base × height ÷ 2. Ellipse = π × a × b, where a and b are the semi-axes, half of the full width and height. A circle is an ellipse with both semi-axes equal to the radius.
With 8 and 5: a rectangle or parallelogram has an area of 40, a triangle 20, and an ellipse with semi-axes 8 and 5 has π × 8 × 5 = 125.6637.
The perpendicular height, measured at a right angle from the base to the opposite corner or side. The length of a sloping side gives the wrong answer.
Choose Ellipse and enter the radius as both semi-axes. A radius of 5 gives π × 5 × 5 = 78.5398.
You do not have to open Area of Shapes to use it. Ask Xenition in plain language and it runs the right tool, then carries the answer into whatever you are working on — a document, a spreadsheet, a deck.