Question

Find the unknown side length of the triangle given the perimeter P. Then classify the triangle by its side lengths.

$P=49\text{in.}$

Short answer

The length of the unknown side of the triangle is 19 in.

The triangle is a scalene triangle.

Step-by-step solution

Step 1. Given Information.

Perimeter of the triangle is given as $P=49\text{in.}$

Length of one side is 18 in.

Length of second side is 12 in.

Step 2. Calculation.

Let the length of the unknown side be as x.

$x+18+12=49$

Now add both numbers together,

$x+30=49$

Subtract 30 from both the sides

$x+30-30=49-30$

This gives us

$x=19\text{in.}$

Step 3. Conclusion.

The length of the unknown side of the triangle is 19 in.

Since, all the lengths of the three sides are different, hence it is a scalene triangle.