Find the area of a triangle two sides of which are 18 cm and 10 cm and the perimeter is 42 cm

The most common way to find the area of a triangle is to take half of the base times the height. Numerous other formulas exist, however, for finding the area of a triangle, depending on what information you know. Using information about the sides and angles of a triangle, it is possible to calculate the area without knowing the height. Find the base and height of the triangle. The base is one side of the triangle. The height is the measure of the tallest point on a triangle. It is found by drawing a perpendicular line from the base to the opposite vertex. This information should be given to you, or you should be able to measure the lengths. • For example, you might have a triangle with a base measuring 5 cm long, and a height measuring 3 cm long. Plug the base and height into the formula. 1 2 So, the area of a triangle with a base of 5 cm and a height of 3 cm is 7.5 square centimeters. Find the area of a right triangle. Since two sides of a right triangle are perpendicular, one of the perpendicular sides will be the height of the triangle. The other side will be the base. So, even if the height and/or base is unstated, you are given them if you know the side lengths. Thus you can use the Area = 1 2 ( b h ) Calculate the semiperimeter of the triangle. The semi-perimeter of a figure is equal to half its perimeter. To find the semiperimeter, first calculate the 1 2 Set up Heron’s formula. The formula is Area = s ( s − a ) ( s − b ) ( s − c ) are the side lengths of the tr...