Mathematics problem a cuboid glass fish tank, 50 cm long, 40 cm wide, three decimeters high Question 1: how many square centimetres of glass do you need to make this fish tank? Question 2: what is the depth of 40 liters of water in the fish tank? Question 3: if you put pebbles, aquatic plants and fish into the water, the water will rise by 2.5cm. What is the total volume of pebbles, aquatic plants and fish?

Mathematics problem a cuboid glass fish tank, 50 cm long, 40 cm wide, three decimeters high Question 1: how many square centimetres of glass do you need to make this fish tank? Question 2: what is the depth of 40 liters of water in the fish tank? Question 3: if you put pebbles, aquatic plants and fish into the water, the water will rise by 2.5cm. What is the total volume of pebbles, aquatic plants and fish?

A:
1、 The fish tank needs at least one bottom and four sides (two or two opposite): S = 50 * 40 + 50 * 30 * 2 + 40 * 30 * 2 = 7400 square centimeter;
2、 40 liter hydration 40000 cubic centimeter, water depth h = 40000 / (50 * 40) = 20 cm;
3、 The water surface has risen by 2.5 cm, and the increased volume v = (50 * 40) * 2.5 = 5000 cubic cm

What is the surface area and volume of a cube with an edge length of 40 cm cut into the largest cylinder?

3.14 × (402) 2 × 40, = 3.14 × 400 × 40, = 50240 (cubic centimeter), 3.14 × (402) 2 × 2 + 3.14 × 40 × 40, = 3.14 × 400 × 2 + 5024, = 1256 + 5024, = 6280 (square centimeter); a: the volume of this cylinder is 50240 cubic centimeter, and the surface area is 6280 square centimeter