To find the perimeter of a triangle, you add up the lengths of all three sides. The basic formula is:

Perimeter=a+b+c\text{Perimeter}=a+b+cPerimeter=a+b+c

where aaa, bbb, and ccc are the lengths of the three sides of the triangle

Steps to find the perimeter:

1. Measure the lengths of all three sides of the triangle, ensuring they are in the same unit.
2. Add these three lengths together.
3. The sum is the perimeter, expressed in the same unit as the side lengths.

Example:

If a triangle has sides of lengths 6 inches, 8 inches, and 10 inches, then its perimeter is:

6+8+10=24 inches6+8+10=24\text{ inches}6+8+10=24 inches

If you only know two sides and the angle between them (SAS triangle), you can use the law of cosines to find the third side, then sum all three sides to get the perimeter. Similarly, if you know two angles and one side (ASA triangle), you can use the law of sines to find the missing sides before calculating the perimeter

Special cases:

• Isosceles triangle (two equal sides): Perimeter = 2a+b2a+b2a+b, where aaa is the length of each equal side and bbb is the third side

• Equilateral triangle (all sides equal): Perimeter = 3a3a3a, where aaa is the length of one side.

In summary, the perimeter of any triangle is the total length around it, found by adding the lengths of all its sides