A triangle is a type of polygon, which has three sides, and the two sides are joined end to end is called the vertex of the triangle. An angle is formed between two sides.

The sum of all three interior angles is equal to 180 degrees.

The exterior angles of a triangle always add up to 360 degrees.

Explanation: To find the area of a triangle with sides of length 5, 6, and 7 units, we can use Heron’s formula.First, we need to find the semi-perimeter,which is half of the perimeter,so we add up all three sides and divide by 2.In this case,the semi-perimeter is 9 units.

Next, we can use Heron’s formula, which is: \$(\sqrt(s(s-a)(s-b)(s-c)))\$ then we get \$ 6 \sqrt(6)\$ square units.