Call the unknown length 2l. Draw a perpendicular bisector of one side through the opposite vertex. This creates two right triangles with sides of 2l, l, and, from the Pythagorean theorem, (l X sq rt 3). The latter of these is the altitude of the triangle, and its base is 2l. The area of any triangle equals one-half the product of the base and the altitude, which in this instance is (sq rt 3) X l2. This area is stated to be 100 cm2, so that l2 = 100/(sq rt 3) = about 57.7; l = about 7.598 cm, and the side length = 15.2 cm, to the justified number of significant digits.
Area = 15.58846 cm2
Side length is about 12 units (11.99963) given an area of 62.35
The side length is 15.2 (15.19671) inches.
The length of the third side of an equilateral triangle is the same as the lengths of both of the other two sides.
If the triangle is equilateral, you simply divide the perimeter by three to find the length of each side. If the triangle is not equilateral, you will need more information to determine the length of each side.
To get the area of an equilateral triangle, you just need to know the length of one side. Multiply the length of one side by the square root of three and then divide the product by four, and you will get the area of the triangle.
Area = 15.58846 cm2
Area of an equilateral triangle is s*(sqrt 3)/2, where s is the length of a side, or: area = s * 0.866666. . .
Side length is about 12 units (11.99963) given an area of 62.35
0.4330 times the length of a side (in square units of length)
389.711 ft2
12
15.2 inches.
15.588 cm2
The side length is 15.2 (15.19671) inches.
The side length is 18.24 (18.23606) inches.
15/3=5 equilateral triangle is a triangle with every side the same length