The perimeter of the scalene triangle is 54.6 cm.
which equation can be used to find the value of b if side a measures 8.7 cm?
8.7 + b = 54.6
17.4 + b = 54.6
26.1 + b = 54.6
34.8 + b = 54.6

the correct question is
The perimeter of the scalene triangle is  cm.
Which equation can be used to find the value of b if side a measure  cm and side c measure  cm?

we know that
the perimeter of a triangle is equal to

equation 1

equation 2

equate equation 1 and equation 2


therefore

the answer is the option D

Set square i think so