If a triangle has sides a, b, and c, the perimeter is

• A. P = 2l + 2w
• B. A = π r^2
• C. P = a + b + c
• D. Sine = opposite/hypotenuse

Answer: (C)

Perimeter is the total distance around a figure, found by adding all its side lengths. For a triangle with sides a, b, and c, the perimeter is a + b + c.

The other options relate to different things: P = 2l + 2w is the perimeter of a rectangle (two times length plus two times width); A = π r^2 is the area of a circle with radius r; Sine = opposite/hypotenuse is the sine ratio used in right-triangle trigonometry.

For a quick check, if the sides are 3, 4, and 5, the perimeter is 3 + 4 + 5 = 12.