# Formula for area of a triangle

The geometry of triangles definitions and formulas for the area of a triangle, the sum of the angles of a triangle, the pythagorean theorem, pythagorean triples and special triangles (the 30-60-90 triangle and the 45-45-90 triangle. Area = ½ bh = ½ × 20 × 12 = 120 knowing three sides there's also a formula to find the area of any triangle when we know the lengths of all three of its sides.

H = height, s = side, a = area, b = base you know that each angle is 60 degrees because it is an equilateral triangle if you look at one of the triangle halves, h/s = sin 60 degrees because s is the longest side (the hypotenuse) and h is across from the 60 degree angle, so now you can find s.

Triangle area = ½ × b × h b = base h = vertical height : square area = a 2 a = length of side: rectangle area = w × h w = width h = height : parallelogram area = b × h b = base h = vertical height: r = radius θ = angle in radians: note: h is at right angles to b: example: what is the area of this rectangle the formula is: area = w.

Areas of triangles the most common formula for finding the area of a triangle is k = ½ bh , where k is the area of the triangle, b is the base of the triangle, and h is the height (the letter k is used for the area of the triangle to avoid confusion when using the letter a to name an angle of a triangle. Learn how to find the area of an obtuse triangle learn how to find the area of an obtuse triangle if you're seeing this message, it means we're having trouble loading external resources on our website if you're behind a web filter, please make sure that the domains kastaticorg and kasandboxorg are unblocked. The area of a polygon is the number of square units inside that polygon area is 2-dimensional like a carpet or an area rug a triangle is a three-sided polygonwe will look at several types of triangles in this lesson to find the area of a triangle, multiply the base by the height, and then divide by 2.

## Formula for area of a triangle

Scalene triangle equations these equations apply to any type of triangle reduced equations for equilateral, right and isosceles are below.

- Intuition for why the area of a triangle is a = 1 2 b h a=\dfrac{1}{2}bh a = 2 1 b h a, equals, start fraction, 1, divided by, 2, end fraction, b, h to see why the formula makes sense, drag the dot all the way to the right.
- There are many different formulas that one can use to calculate the area of a triangle this is the most common formula used and is likely the first one that you have seen observe that this is exactly half the area of a rectangle which has the same base and height.