Answer:
b = 45.9 - c
Step-by-step explanation:
A scalene triangle has non of its sides equal.
Perimeter = 54.6
side a = 8.7 cm
side b = unknown
side c = unknown
Perimeter of a shape is sum of all its sides.
Perimeter = a + b + c
54.6 = 8.7 + b + c
Making b the subject
b = 54.6 - 8.7 - c
b = 45.9 - c
The value of b is (45.9 - c)