Hello, magentarita!

Law of Cosines . . .A surveyor is mapping a triangular plot of land.

Two of the sides are 400 and 200 yards and the included angle is 50°.

(a) What is the length of the third side of the triangle, to the nearest yard?

yards

Formula: .(b) What is the area of this plot of land, to the nearest square yard?

. . The area is one-half the product of two sides and the sine of the included angle.

Therefore: . square yeards.