(1) In a square pool, build a 5-meter-wide lawn around him with an area of 400 square meters. How long is the side of this square pool? How big is the area?

(2) Four identical small squares make up the picture below. The area of a big square is 8 1 cm2, and the width of a small square is 2 cm. What is the area of a small square?

(3) In the picture below, the area of the big square is 36 square decimeters, so the small square is 36 square decimeters. What is the area of this small square?

(4) The area of the big square is 36 square decimeters, so what is the area of the small square which is also the audio-visual part?