Image caption, For a right-angled triangle, the base and the perpendicular height are the two sides that are at right angles. The perpendicular height is the perpendicular measurement that gives ...

They often identify them solely based on their resemblance to prototypes: e.g., a shape will be called a triangle if it looks like an equilateral triangle with a horizontal base – all others ... with ...

Rectangles, arches, and triangles are the most common shapes used to build big structures. What happens when you push the side of a rectangle? The rectangle is a wobbly, unstable shape.