SOLUTION
Given the question in the image, the following are the solution steps to answer the question
STEP 1: Write the formula for finding the perimeter of a triangle
[tex]\begin{gathered} \text{Perimeter of a triangle is the sum of all the sides of the triangle} \\ \text{That is: }a+b+c_{} \\ \text{where a,b and c are the sides} \end{gathered}[/tex]
STEP 2: Write the given sides
[tex]\begin{gathered} \text{Let a=7.3}cm \\ \text{Let b=2.94}cm \\ \text{Let c=unknown}=x \\ \text{Perimeter}=14.8cm \end{gathered}[/tex]
STEP 3: Substitute the values into the formula
[tex]\begin{gathered} \text{Perimer}=a+b+c_{} \\ 14.8=7.3+2.94+x---equation\text{ 1} \\ By\text{ subtracting x from both sides} \\ 14.8-x=7.3+2.94+x-x \\ 14.8-x=7.3+2.94----\text{equation 2} \\ U\sin g\text{ equation 1 again,} \\ 14.8=7.3+2.94+x \\ 14.8=10.24+x \\ 14.8=x+10.24-----equation\text{ 3} \end{gathered}[/tex]
STEP 4: Choose the equation that could not be used to find the third side
The equation in option B can be seen in equation 1 in Step 3
The equation in option C can be seen in equation 3 in Step 3
The equation in option D can be seen in equation 2 in Step 3
Hence, the equation that could not be used to find the third side is the equation in option A
x - 14.8 = 2.94 + 7.3
