# Examples for 8th grade - page 9

- Kites

Boys run kite on a cable of 68 meters long. What is the kite altitude, if the angle from the horizontal plane is 72°? - Ladder

Ladder 8 m long is leaning against the wall. Its foot is 1 m away from the wall. In which height ladder touches the wall? - Trapezoid

Calculate area of trapezoid ABCD with sides |AD|= 57 cm, |DC|=30 cm, |CB|=7 cm, |AB|=40 cm.. - VAT

John paid 100 Euros in store for purchase. Calculate value added tax (VAT), which paid in purchase, if the VAT rate is 20%. - R Trapezium

Rectangular trapezium has bases 12 and 5 and area 84 cm^{2}. What is its perimeter? - One half

One half of ? is: ? - Air mass

What is the weight of the air in a classroom with dimensions 10 m × 10 m × 2.7 m ? The air density is 1.293 kg/m^{3}. - The cyclist

The cyclist went from village to town. First half of journey went at 20 km/h. The second half of the journey, which mostly fell, went at 39 km/h. All journey took 88 minutes. Calculate the distance from the village to the town. - 2nd class variations

From how many elements you can create 6972 variations of the second class? - Arc and segment

Calculate the length of circular arc l, area of the circular arc S_{1}and area of circular segment S_{2}. Radius of the circle is 33 and corresponding angle is ?. - Gear wheels

Two gear wheels, which fit together have the number of teeth z_{1}=58 and z_{2}=149. Calculate the speed of the first wheel, if the second wheel rotates 1232 revolutions per minute. - Triangle

Can be rectangular triangle equilateral? - Angles

Determine the interior angles of a rhombus with area 319.1 cm^{2}and perimeter 72 cm. - Quarter circular

The wire that is hooked around the perimeter of quarter-circular arc has length 3π+12. Determine the radius of circle arc. - Workers

Workers A and B will done work together for 15 days. They worked together 13.5 days. Then A worker became ill and worker B finish the job alone for 7.5 days. If every worker was working alone, how many days took whole work for worker A and B? - Prism X

The prism with the edges of the lengths x cm, 2x cm and 3x cm has volume 20250 cm^{3}. What is the area of surface of the prism? - Pyramid roof

1/3 of area of the roof shaped regular tetrahedral pyramid with base edge 9 m and height of 4 m is already covered with roofing. How many square meters still needs to be covered? - Car range

Calculate the maximum range of car, if you can spend 10 euros, price of diesel is 1.55 Eur/l and car consumption is 3 l/100 km. - Inflation

Once upon a time, tsar owned a money printer and printed and printed. The result of printing money prices went up,in the first year 3.9 %, in the second 6%, in the third 4.7% and in the fourth 5.5%. Then tsar was failed in election. Calculate the aver - Train and car

The train and the car started at a constant speed to journey. When the train travels 87 km, the car travels 97 km. How many km travels the train when the car travels 87 km?

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