Math practice for 13 year olds - page 187 of 428
Number of problems found: 8555
- From plasticine
Michael modeled from plasticine a 15 cm high pyramid with a rectangular base, with the sides of the base a = 12 cm and b = 8 cm. From this pyramid, Janka modeled a rotating cone with a base diameter of 10 cm. How tall was Janka's cone? - Two vases
Michaela has two vases in her collection. The first vase has the shape of a cone with a base diameter of d = 20 cm; the second vase has the shape of a truncated cone with a lower base of d1 = 25 cm and a diameter of the upper base d2 = 15 cm. Which vase c - Line ratio comparison
Compare line lengths by ratio and proportion. a) AB = 2 cm, | KL | = 8 cm (b) | EF | = 28 cm, | MN | = 21 cm - Helena Jane savings
Helena had 20% more savings than Jane. They have saved 1804 CZK. How much have Helena and Jane held? - Pyramid height calculation
In a regular quadrilateral pyramid, the base edge a = 6cm, and the side edge b = 10cm. Calculate the height of the pyramid. - Cube dimension calculation
The cube has an area of 486 dm². Calculate the length of its side, its volume, the length of the body, and wall diagonals. - Calculate a prism
Calculate the volume and surface area of a prism whose height is 16cm and whose base is a right triangle with sides of 5cm and 12cm and a hypotenuse of 13cm. - Pool pump calculation
The pool for swimmers has dimensions of 25m, 10m, and 2.8m, and the children's pool is only 10m, 4m, and 1m. The pump will change all the water in the swimming pool in 9 hours. How long does it take for the same pump to pump out the water in the children' - Train distance calculation
Two trains left London bound for Brighton. One at 14:00 and the other at 14:20. One train moves at a speed of 120/km per hour. Kinds 150/km per hour. How far apart will they be at three o'clock? - Well excavation transport
The company is to dig a well 25 m deep with a radius of 0.8 m. How many cars that can be loaded with 12 cubic m will be needed to transport the excavated soil if it is calculated that the soil will increase in volume by 10% when excavated? - Isosceles triangle
An isosceles triangle has an angle against the base that measures 55°. What is the size of the angle at the base of an isosceles triangle? (Calculation and procedure) - Regular quadrilateral pyramid
Find the surface area of a regular quadrilateral pyramid with a volume of 24 dm³ and a height of 45 cm. - Six painters
Six painters paint an area of 120 m² in 4 hours. How long does it take for 12 painters to paint 480 m² with the same performance? - Percentage calculation examples
Calculate these four examples as percentages: 5% of 650 meters 30% of 18kg 351% if 9% is 1/3 62.5% if 15% is 0.75 - Antenna mast
The antenna mast is 26 meters high. It is fixed by four steel cables suspended 1.6 meters below the highest point of the mast and anchored to the ground at the vertices of a square with a side length of 14 meters. The mast is erected in the center of this - Father daughter age
When the father was 31, the daughter was eight years old. Now, a father is twice as old as a daughter. How old is her daughter? - Surface of the cuboid
Find the surface of the cuboid if its edges have the dimensions a, 2/3a, and 2a. - Pond radius calculation
Mr. Marek wants to build a circular pond in his garden. He wishes the perimeter of the pond in meters and the area in square meters to be expressed in the same numbers. What is the radius of the pond? - Freezer box calculation
The freezer box has internal dimensions of 900 mm, 0.75 m, and 6 dm. 30% of the space is filled with frozen peppers packed in boxes measuring 150mm, 100mm, and 50mm. How many boxes are in the box? - A cliff
A line from the top of a cliff to the ground passes just over the top of a pole 5 ft high. It meets the ground at a point 8 ft from the base of the pole. The point is 93 ft from the base of the cliff. How high is the cliff?
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