To find the area of a triangle, it is possible to use one of numerous formulas. Choose a formula depending on what data are already known.
It is required to you
- knowledge of formulas for finding of the area of a triangle
Instruction
1. If you know the size of one of the parties of a triangle and size of height lowered on this party from opposite by it a corner, then it is possible to find the area on the following formula: S = a*h/2 where S is the area of a triangle, a - one of the parties of a triangle, and h - height which is carried out to the party of a.
2. If two parties and size of a corner between them are known, then use such option of the previous formula: S = a*h/2 = a*b*sinα/2, where α - a corner between the parties of an and b.
3. There is the known formula for determination of the area of a triangle if three of its parties are known. It is called Heron's formula. For simplification of its record enter intermediate size - poluperimetr: p = (a+b+c)/2 where a, b, c are the parties of a triangle. Then Heron's formula looks as follows: S = (p(p-a) (p-b) (p-c)) ^½, ^ means exponentiation.
4. Let's assume that one of the parties of a triangle and three corners is known to you. Then it is easy to find the area of a triangle: S = a²sinα sinγ / (2sinβ), where β - a corner, opposite to the party of a, and α and γ - corners, adjacent to the party.