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 ...

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 ...

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.

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 ...

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 ...

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 which 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 ...

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 ...