Maths practice for 12-year-olds - page 176 of 350

Number of problems found: 6986

Trapezoidal prism
Calculate the volume of a prism with a trapezoidal base with side a = 6 dm, side c = 4 dm, and height of the prism = 8dm. The height of the trapezoid is va = 3dm.
Brass
Brass is an alloy of copper and zinc in a ratio of 3:2. How many grams does a component that requires 270 g of copper weigh?
Central angle
The circle has a diameter of 46 cm. What is the arc length that corresponds to a central angle of 30°?
Drivers
Driver Franta and driver Karel are friends. They leave the start-stop at the same time in the afternoon - at 13.30. When will they meet again if Franta goes around his route in 50 minutes and Karel in 40 minutes?
Planetarium's 24241
The planetarium's dome is shaped like a hemisphere with a diameter of 17 m. Determine the size of the projection area
Revolutions 24121
The white wheel has 24 teeth. The black wheel has fewer teeth than the white wheel. Both wheels return to their initial position for the first time after two revolutions of the white wheel. How many teeth does the black wheel have?
The convoy
During a military exercise, the convoy left the camp at 5 hours at a speed of 40 km/h. Half an hour later, the commander sent a motorcycle clutch at a speed of 70 km/h. How long before the motorcycle clutch reaches the column?
Continuously 24061
The Pelikan's account was continuously paid the following amounts: 2,000, 4,500, 6,100, 2,100, 3,000, 1,700, 2,600, 2,000 Find average storage amounts.
Triangular 24001
The tent's floor consists of a square with a side of 2.4 m, and the front and back wall is an isosceles triangle with a height of 1.6 m. Calculate the volume of air in the tent in liters. (Laid triangular prism.)
Three-fifths 23961
Three-fifths of the orchard trees are apple trees. One-third are cherry trees. The remaining five trees are pear trees. How many trees are in total growth in the orchard?
The shadow
The shadow of a 1 m high pole thrown on a horizontal plane is 0.8 m long. At the same time, the shadow of a tree thrown on a horizontal plane is 6.4 m. Determine the height of the tree.
Quadrilateral pyramid
Calculate the volume of a regular quadrilateral pyramid, which has the size of the base edge a = 12 cm and a height of 11 cm.
Diameters of euro coins
When paying, we use euro coins with the following diameters: The 10-cent coin has a diameter of 19.75 mm. The 20-cent coin has a diameter of 22.25 mm. The 50-cent coin has a diameter of 24.25 mm. Find out in what ratio the diameters of these coins are.
Quadrilateral 23881
Calculate the height of a regular quadrilateral prism whose base is a rhombus. The edge in the base is 7 cm long, the opposite edges are 5 cm apart, and we also know that the entire body has a volume of 1dm³.
Waste bin
The cube-shaped potato peel waste bin is 80 cm high. How many liters of waste can we put into it if we know that the dimensions of the base are 40 cm and 50 cm, the basket is already full to exactly half its height, and as soon as the waste reaches the li
Length of the arc
What is the arc length of a circle k (S, r=68mm), which belongs to a central angle of 78°?
Centimeter 23781
Calculate the diameter of a cylinder 7.5 dm high with a volume of 0.6 hl. Express the result to the nearest centimeter.
Kilometers 23721
Eva left the cinema at a speed of 4 km/h. Half an hour later, Adam left after her with the mobile phone that Eva had forgotten at the cinema. It was moving at a speed of 6 km/h. How long will it take Adam to catch up with Eva, and how many kilometers from
4-member 23681
A four-member group planned to paint the school for ten days. After two days, one member fell ill. If they worked with the same effort, how many days were the school painted?
Diggers
The excavation was carried out in 4 days, and five workers worked on it for 7 hours daily. Determine how long it would take to excavate if seven workers worked on it 8 hours a day.

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