(2800-600)÷2= 1 100

Because the area of a triangle is equal to the base times the height divided by 2.

According to the meaning of the question, this is a right triangle

So the height is 2x 1 100÷55=40.

The height of this 40 is the width of the rectangle

The area of a rectangle is length times width.

So length = area divided by width =2800÷40=70.

This rectangle is 70 meters long and 40 meters wide.