# Examples for 8th grade - page 7

- Engineer Kažimír

The difference between politicians-demagogues and reasonable person with at least primary education beautifully illustrated by the TV show example. "Engineer" Kažimír says that during their tenure there was a large decline in the price of natural gas, pri - Cube zoom

How many percents do we increase the volume and surface of the cube if we magnify its edge by 38 %? - Rectangle - sides ratio

Calculate area of rectangle whose sides are in ratio 3:13 and perimeter is 673. - Rhombus and inscribed circle

It is given a rhombus with side a = 6 cm and the radius of the inscribed circle r = 2 cm. Calculate the length of its two diagonals. - Car

Car goes from point A to point B at speed 86 km/h and back 53 km/h. If they goes there and back at speed 67 km/h trip would take 10 minutes shorter. What is distance between points A and B? - Tare

Gross weight of shipment is 5188 kg and its tare is 5.6%. Calculate the net weight of the shipment. - Maximum area of rhombus

Calculate the interior angles at which equilateral rhombus has a maximum area. - Isosceles right triangle

Calculate the area of an isosceles right triangle whose perimeter is 377 cm. - Gear

Two gears, fit into each other, has transfer 2:3. Centres of gears are spaced 82 cm. What are the radii of the gears? - Rectangle

In rectangle ABCD with sides |AB|=19, |AD|=16 is from point A guided perpendicular to the diagonal BD, which intersects at point P. Determine the ratio ?. - Cone

Circular cone of height 15 cm and volume 5699 cm^{3}is at one-third of the height (measured from the bottom) cut by a plane parallel to the base. Calculate the radius and circumference of the circular cut. - Motion

Cyclist started at 9:00 from point S to point T. After 10 minutes, followed him at the same speed the second cyclist. Walker, which went from T to S, started at 9:35. After 71 minutes he met the first cyclist and after next 8 minutes the second cyclist. Di - Daily average

Calculate the average temperature during the day, when 15 hours was 20 °C and 9 hours was 13 °C. - Expansion

If one side of the rectangle is larger 4-times and second 2-times, what percentage increases the area of rectangle? - Tangents

To circle with a radius of 41 cm from the point R guided two tangents. The distance of both points of contact is 16 cm. Calculate the distance from point R and circle centre. - Radians

Convert 270° to radians. Write result as multiple of number π. - Sea water

Mixing 62 kg of sea water with 84 kg rainwater is created water containing 3.1% salt. How many percent sea water contains salt? - Lathe

From the cube of edge 37 cm was lathed maximum cylinder. What percentage of the cube is left as waste after lathed? - Cu thief

The thief stole 122 meters copper wire with cross-section area of 95 mm^{2}. Calculate how much money gets in the scrap redemption, if redeemed copper for 5.5 eur/kg? The density of copper is 8.96 t/m^{3}. - Guests

How many ways can 9 guests sit down on 11 seats standing in a row?

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