These shapes are all regular polygons. A regular triangle is called an equilateral triangle. A regular quadrilateral is called a square. Irregular polygons are shapes that have sides and angles of ...

Save guides, add subjects and pick up where you left off with your BBC account. A triangle is a polygon. It is a closed 3-sided shape made up of straight lines. The ‘tri-’ part of the word ...

The sum of the angles inside any polygon can be found by splitting the polygon into triangles. The number of triangles that a polygon can be divided into is always two less than its number of sides.

A scalene triangle has 3 sides of different lengths and 3 unequal angles. An isosceles triangle has 2 sides of equal length. The dashes on the lines show they are equal in length. The angles at ...

A scalene triangle has 3 sides of different lengths and 3 unequal angles. An isosceles triangle has 2 sides of equal length. The dashes on the lines show they are equal in length. The angles at ...

That’s why you then multiply by 180° - that’s the sum of the internal angles within a triangle. Here's how you would change the formula for the different polygons below. You can even try ...

A scalene triangle has 3 sides of different lengths and 3 unequal angles. An isosceles triangle has 2 sides of equal length. The dashes on the lines show they are equal in length. The angles at ...

To find the sum of interior angles in a polygon divide the polygon into triangles. The sum of interior angles in a triangle is 180°. To find the sum of interior angles of a polygon, multiply the ...

To find the sum of interior angles in a polygon divide the polygon into triangles. The sum of interior angles in a triangle is 180°. To find the sum of interior angles of a polygon, multiply the ...

That’s why you then multiply by 180° - that’s the sum of the internal angles within a triangle. Here's how you would change the formula for the different polygons below. You can even try ...