# The perimeter of the rectangle is 40dm, and the width is 4cm less than the length. How many square decimeters

December 31, 2020 | education

| **The perimeter of the rectangle is 40dm, and the width is 4cm less than the length. How many square decimeters is the area of a rectangle less than the area of a square with the same perimeter?**

Given:

Ppr = 40dm

L – the length of the rectangle

H = L-0.4 – rectangle width

Sq = (Ppr / 4) ^ 2 = 100 dm2

Spr = L * (L-0,4)

Ppr = 2 * L + 2 * (L-0.4) = 4L-0.8

40 = 4L-0.8

4L = 40.8

L = 10.2 dm

Spr = L * (L-0.4) = 10.2 * (10.2-0.4) = 10.2 * 9.8 = 99.96 dm2

Sq-Spr = 100 dm2-99.96 dm2 = 0.04 dm2 – the difference between the required areas

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