Maths practice for 12-year-olds - page 176 of 351
Number of problems found: 7018
- Similar triangles
In the triangle DEF is DE = 21 cm, EF = 14.7 cm, DF = 28 cm. The triangle D'E'F' is similar to the triangle DEF. Calculate the lengths of the sides of the triangle D'E'F' if the similarity coefficient is one-seventh. - Order 2
Two production lines are available to fulfil an urgent order. The original line can produce the required goods in 15 hours, while the newer line, which has not yet been started up, could have the goods ready in 10 hours. The original line can be launched - Shoemaker
Both the shoemaker and his apprentice repaired his shoes. The apprentice worked for six days and repaired ten pairs of shoes daily. The shoemaker did the same job for four days. How many pairs of shoes did the shoemaker repair per day? - Filling the pool
How many liters of water must be poured into a pool 25 m long, 800 cm wide, and 20 m deep? The pool should be filled to 3/4 of its depth. How many euros will you pay for pool tiling, and a square meter of tiling costs 20 euros? - Cone surface volume
The rotating cone has a base circumference of 62.8 cm. And a height of 0.7 dm. Calculate its surface area and volume. - Cylinder container
The cylindrical container with a diameter of 1.8 m contains 2,000 liters of water. How high does the water reach? - Cylinder surface calculation Calculate the surface of the paper cylinder (without lid), which has the following dimensions: bottom radius: 7 cm, cylinder height: 22 cm.
- Quadrilateral pyramid
Calculate the volume of a quadrilateral pyramid, the base of which has the shape of a rectangle with dimensions a = 6 cm, b = 4 cm, and height v = 11 cm - Ferris wheel speed
The Ferris wheel in London has a diameter of 135 meters, and one turn takes about 30 minutes. At what speed per second do the cabins move around the perimeter of the London London Eye? - The trench
Calculate how many cubic meters of soil need to be removed from the excavation in the shape of an isosceles trapezoid. The top width is 3 meters, the lower width is 1.8 m, the excavation depth is 1 m, and the length is 20 m. - Sapling planting calculation
In the forest, there are 84 workers employed in planting saplings. Working 10 hours a day, they would finish the job in 24 days. After 7 days, 14 workers leave. How long will it take the others to finish planting the saplings if they work 12 hours a day f - Plane dusting distance
The plane dusted the field in 25 minutes at 252 km/h. How many kilometers has it flown? - Pyramid base calculation
The volume of the right 4-side pyramid is 138 m3, and its height is 9 m. Calculate the area of the base and the edge of its base. - Cone mesh drawing Sketch the cone mesh and add the side length, the arc length of the circle, and the circle length to it, if you know: the side length of the cone: s = 51.9 cm cone base circumference = O = 151 mm.
- Gear turn calculation
Two gears – one smaller and one larger rotate so that the teeth of both wheels mesh together. The first wheel has 18 teeth, the second 27. How many times does each wheel turn before returning to its starting position? - Skirt fabric calculation
They bought fabric to sew a skirt in a tailor's salon. If they sewed skirts 50 cm long, they would sew 70 of them. How many skirts will they sew if they are 70 cm long? - Driving distance calculation
If I drive 30 km in two hours, how many kilometers will I drive in 2.5 hours if I drive at the same speed? - Tractor plowing calculation
Tractor operator Formánek can plow Mr. Kafka's land in 30 hours using a plowing set with a four-blade plow. The tractor driver Divíšek, plowing with a five-blade plow, can plow Kafka's land in 24 hours. In how many hours will the two tractor drivers plow - Balloon fabric calculation
How much fabric is needed to sew a spherical hot air balloon with a diameter of 15 m? How much air is needed to inflate the balloon? - Square tile space
What is the smallest square space we can tile with tiles measuring 25 x 15 cm, knowing there will be no need to cut them? How many tiles will we use?
Do you have homework that you need help solving? Ask a question, and we will try to solve it. Solving math problems.
