Which expression can be used to find the area of triangle rst?

(8 ∙ 4) - 1/2 (10 + 12 + 16)
(8 ∙ 4) - (10 + 12 + 16)
(8 ∙ 4) - 1/2 (5 + 6 + 8)
(8 ∙ 4) - (5 - 6 - 8)

We start by drawing a rectangle around the triangle as shown in the diagram below

Area of RST = Area of rectangle - (area of triangle A + area of triangle B + area of triangle C)

Area of RST = (8×4) - [ (1/2×8×2) + (1/2×4×3) + (1/2×5×2) ] ⇒ we factorise the 1/2 out of the expression for the area of triangle A, B, and C

Area of RST = (8×4) - 1/2 (16+12+10)