Question

Two sides of a triangle measure 18 meters and 11 meters. If the perimeter of the triangle is 37 meters, what is the length of the third side?12 m8 m66 m30 m

Answer 1

Since the triangle has 3 sides, then

The perimeter of the triangle is the sum of the lengths of the 3 sides

`P=s_1+s_2+s_3`

Since the perimeter is 37 meters, then

`P=37`

Since the lengths of 2 sides are 18 meters and 11 meters, then

`\begin{gathered} s_1=18 \\ s_2=11 \end{gathered}`

Substitute them in the rule above

`\begin{gathered} 37=18+11+s_3 \\ 37=29+s_3 \end{gathered}`

Subtract 29 from both sides

`\begin{gathered} 37-29=29-29+s_3 \\ 8=s_3 \end{gathered}`

The length of the 3rd side is 8 meters

The answer is the 2nd choice