# Examples for 8th grade - page 40

- RT 11

Calculate the area of right tirangle if its perimeter is p = 46 m and one cathethus is 18 m long. - CD disc

A compact disc has a diameter of 11.8 cm. What is the surface area of the disc in square centimeters? - Diameter

If the endpoints of a diameter of a circle are A(10, -5) and B (8, 7), what is the radius of the circle? - Carpenter

From wooden block carpenter cut off a small cuboid block with half the edge length. How many percent of wood he cut off? - Racer

The first racer run at a speed 12 m/s and is 470 meters before the finish and ahead 22 meters before second competitor. At what speed must run the second racer to catch first racer at the finish line? - Plastic pipe

Calculate weight of the plastic pipe with diameter d = 60 mm and length 400 cm if the wall thickness is 6 mm and the density of plastic is 1228 kg/m^{3.} - Task

I have homework. The cube has an edge 11 cm long and I must find wall and body diagonal. - Rhombus and inscribed

Rhombus has side a = 72 cm, the radius of the inscribed circle is r = 10 cm. Calculate the length of its two diagonals. - Angles

Determine the interior angles of a rhombus with area 240.6 cm^{2}and perimeter 64 cm. - Acids

76% acid was make from same acid of two different concentrations. Amount weaker acid to the stronger acid is in ratio 2:1. What was the concentration of the weaker acid, if stronger had 94% concentration? - Motion

From two different locations distant 104 km started against car and bus. The car started at 5:30 with average speed 58 km/h. Bus started at 6:40 with average speed 79 km/h. When they meet? How many kilometers went the bus? - Rotation

Right triangle with legs 9 cm and 16 cm rotate around longer leg. Calculate the volume and surface area of the formed cone. - Numbers

Determine the number of all positive integers less than 2937474 if each is divisible by 11, 23, 17. What is its sum? - Tinsmith

Tinsmith construct chimney pipe 126 cm long and 11 cm wide. What are the dimensions of the sheet will have to prepare for the construction of a pipe when the plate overlap at the joint add $x cm width of the plate? - Rates

When gas consumption, the consumer may choose one of two rates: rate A - which pays 0.35 € per 1 m^{3}of gas a flat monthly fee of 3.6 € (regardless of consumption) rate B - which pays 0.295 € per 1 m^{3}of gas a flat monthly fee of 8.3 € From what monthl - Two friends

Two friends met as a good man perish together for a beer. After recovery the most important topics (politics, women, football ...), one asks: - And how many do you have children? - I have 3 children. - And how many years have? Friend already not want to an - Apples

Apples I picked 600 kg this year. Autumn's apples was 4 times more than the summer. How many kg's I picked the summer and how much winter apples? - Rings groups

27 pupils attend some group; dance group attends 14 pupils, 21 pupils sporty group and dramatic group 16 pupils. Dance and sporting attend 9 pupils, dance and drama 6 pupil, sporty and dramatic 11 pupils. How many pupils attend all three groups? - Dried apples

How many kilograms of fresh apples id needed to 120 kg of dried apples when from 0.4 tons of fresh apples we get 75 kg of dried apples? - Interst on savings

The bank offers 1.6% interest. How many euros have to insert at the beginning if we received € 15 on the interest?

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