Can someone tell me how to find the answer to this problem.

Area of a triangle is one-half base times height, ant the area of a rectangle is length times width.

The triangle on top has a base of 14 and height of 11, so the area is 0.5*14*11=77 mm^2

The rectangle in the middle and a width of 14 and height of 4. The area is 14*4=56 mm^2

Triangle on bottom has area 0.5*14*3=21 mm^2

Add all the areas.

77+56+21= 154 mm^2