Answer:
16 cm
Step-by-step explanation:
Let the three consecutive even integers representing the sides of the triangle PQR be x, (x +2) and (x + 4).
Since, perimeter of triangle PQR = 42 cm
[tex] \therefore \: x + (x + 2) + (x + 4) = 42 \\ 3x + 6 = 42 \\ 3x = 42 - 6 \\ 3x = 36 \\ x = \frac{36}{3} \\ x = 12 \\ \\ \because \: longest \: side = x + 4 \\ \therefore \: longest \: side = 12 + 4 \\ \red{ \bold{ \therefore \: longest \: side = 16 \: cm}} \\ [/tex]
