# Examples for 8th grade

- Rotating cone

Calculate the volume and the surface area of a rotating cone of base radius r = 2.3 dm and a height h = 46 mm. - Pyramid 4sides

Calculate the volume and the surface of a regular quadrangular pyramid when the edge of the base is 4 cm long and the height of the pyramid is 7 cm. - Cube diagonals

Determine the volume and surface area of the cube if you know the length of the body diagonal u = 216 cm. - Roof 8

How many liters of air are under the roof of tower which has the shape of a regular six-sided pyramid with a 3,6-meter-long bottom edge and a 2,5-meter height? Calculate the supporting columns occupy about 7% of the volume under the roof. - Sputnik

The first Earth satellite was flying at speed 8000 m/s. At that rate he circled the earth in 82 minutes. Jet flies at an average speed 800 km/h. How long would it take circle the earth round? - Pyramid

The pyramid has a base rectangle with a = 6cm, b = 8cm. The side edges are the same and their length = 12.5 cm. Calculate the surface of the pyramid. - Folded square

ABCD is a square. The square is folded on the midpoint of AB and A is folded onto the fold, creating a shaded region. The perimiter of the shaded figure is 75. Find the area of square ABCD - Cuboid and ratio

Cuboid has dimensions in ratio 1:2:6 and the surface area of the cuboid is 1000 dm^{2}. Calculate the volume of the cuboid. - Cylindrical tank

Cylindrical tank holds 600hl water and is deep 2.5 m. Calculate the diameter of the cylinder. - Hexagonal pyramid

Regular hexagonal pyramid has dimensions: length edge of the base a = 1.8 dm and the height of the pyramid = 2.4 dm. Calculate the surface area and volume of a pyramid. - Potatoes bags

I have three bags with 21 kg potatoes. The first bag is 5.5 kg more than in the second bag and the third is 0.5 kg more than in the second bag. Determine how many kgs of potatoes is in each bag. - Regular triangular prism

Calculate the surface area of body of regular triangular prism, when the length of its base edge is 6.5 cm and height 0.2 m. - Tree shadow 3

What is the diameter of a tree around which is 3m 9dm 7cm long rope wrapped? How big is its cross-sectional area? - Sawmill factory

Peter works in the factory. The bus stop is 10 km from the factory. Therefore, always when the bus arrives for Peter, the driver leaves factory and takes him to work. They are coming at the saw exactly at 8:00. Today the bus arrived 11 minutes earlier and - Alcohol mixture

From 55% and 80% alcohol we have to produce 0.2 kg of 60% alcohol. How many of them do we use in solution? - Water reservoir

The reservoir shape of a cylinder having a diameter 8 m and a height 2.8 m. The device indicates that the reservoir contains 800 hectoliters of water. Calculate how much % of volume is used. - Price increase

A 20 percent price increase meant a 90-crown raise. How many cost a product after? - Gasoline tank cylindrical

What is the inner diameter of the tank, which is 8 m long and contains 40 cubic cubic meters of gasoline? - Collection

John has collected half a bucket of raspberries in 45 minutes, Eva collects the whole bucket in an hour. How many minutes it would take to fill a bucket if the two children work together? - Scale of map

James travels one kilometer in 12 minutes. The route walked for half an hour measured on the map 5 cm. Calculate how many kilometers James walked for half an hour. Find the scale of the map.

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