i never understood cross roads questions. explain plzzzzzz

Lets go through an example on cross roads.

Two cross roads each of width 5 cm run at right angles through the center of rectangular park of length 70 m and breadth 45 m and parallel to the sides of the rectangle . Find the area of the roads.

Solution:

We can draw the following figure.

Let ABCD be the rectangular park then EFGH and IJKL are the two rectangular roads with width 5 cm.

Since opposite sides of rectangle are equal in lengths,

⇒ EH = MN = OP = FG = IL = MP = ON = JK = 5 cm 

and AD = EF = HG = BC = 70 m = 7000 cm

and AB = IJ = LK = DC = 45 m = 4500 cm

Now area of roads = Area of EFGH + Area of IJKL – Area of MNOP

= ((7000 × 5) + (4500 × 5) – (5 × 5)) cm²

= (35000 + 22500 – 25) cm²

= 57475 cm²

= 5.7475 cm²

Hope this clears your doubt.