Theorm [ a^2+b^2=c^2] to find the length of that line, which is now the height. After finding your height, substitute your values for base and height into the formula for area of a triangle to find the area. Finding the height of a triangle depends on the type of triangle you are working with. You could also substitute it into sin60^@, cos30^@, tan30^@, or tan60^@ to find the height. Area of equilateral triangle. Here are the formulas for area, altitude, perimeter, and semi-perimeter of an equilateral triangle. An equilateral triangle is a triangle with all three sides equal and all three angles equal to 60°. Applying Pythagoras theorem in right-angled triangle ABD, we get: Hence, the height of the given triangle is 6√3 cm. Let ABC be the equilateral triangle with AD as an altitude from A meeting BC at D. Then, D will be the midpoint of BC. 2.) As the name suggests, ‘equi’ means Equal, an equilateral triangle is the one where all sides are equal and have an equal angle. Find the length of height = bisector = median if given side ( L ) : height bisector and median of an equilateral triangle : = Digit 1 2 4 6 10 F Finding the Height of a Triangle. The equilateral triangle ABC has X as its side. How to find the height of an equilateral triangle. The diagram at the right shows when to use each of these formulas. The height of an equilateral triangle is 1 0 c m. Its area is. Let us find its height. Also, does it matter which side you choose as your base? A. To find the height we divide the triangle into two special 30 – 60 – 90 right triangles by drawing a line from one corner to the center of the opposite side. All three heights have the same length that may be calculated from: h = a * √3 / 2, where a is a side of the triangle This will also cut your base in half. To find the area of an equilateral triangle, you need to calculate the length of half the side length and substitute it into the Pythagorean theorem to find the height. (18 / 3 = 6). To find the height of an equilateral triangle , follow these steps: 1.) In the equilateral triangle ABC of side «a»: ⇒ S = ½.a.h …. Then use the Pythagreom (sp?) Example 2: If you are given area A and you want to calculate perimeter P then you need to make two steps to get the solution. if a perpendicular AD is drawn from A to side BC, then AD is the height. If the perimeter of an equilateral triangle is 18 and its area is 15.6 square units, what is the measure of its height? D is mid point of BC.Therefor BD=DC=X/2. Example 1: If you are given altitude h and you want to calculate side a, then you need to use formula which connects h and a.. The internal angles of the equilateral triangle are also the same, that is, 60 degrees. Place a line from the vertex to the base of the triangle forming two right triangles. Since this is an equilateral triangle and we know its perimeter is 18, we can figure out that each side has a length of 6. This segment will be the height, and will be opposite from one of the 60 degree angles and adjacent to a 30 degree angle. The area of an equilateral triangle (S) is calculated from the following figure: We know that the area of a triangle is ½(base x height).