# Examples for 8th grade - page 47

- Unknown number 10

Number first increased by 30%, then by 1/5. What percentage we've increased the original number? - Square and circle

Into square is inscribed circle with diameter 10 cm.What is difference between circumference square and circle? - Again saw

From the trunk of the tree we have to a sculpture beam with rectangular cross-section with dimensions 128 mm and 140 mm. What is the trunk smallest diameter? - Square roots

What is equal to the product of the square roots of 540225? - Cars

Cars started at 7:00 AM. From point A car run at 40 km per hour, from B car run 70 km per hour. Between A and B is 250 km long road. When and where will meet (measured from point A)? - Rectangle - sides 3

If in the rectangle ABCD we enlarge the side a by 5 cm and decrease the side b by 2 cm, the rectangle area will be reduced by 5 cm². When we decrease the length of the side a by 4 cm and and at the same time we increase the length of side b by 3 cm we incr - Two cars

Car A1 goes at average speed of 133 km/h and the second car A2 goes at 128 km/h. How many second will it take car A1 to circulate car A2? Assume that both cars are 4.7 meters long and the safety gap between cars is 2.7 meters. - Flowerbed 2

Around the square flower bed in a park is sidewalk 1.4 m wide. The area of this sidewalk is 125 m^{2.}What is the area of the flowerbed? - Tram

In the three-part tram went 109 passengers in front of others, 92 after others and in the middle half of all. How many passengers went in tram total? - Ice cream in cone

In the ice cream cone with a diameter of 3.6 cm is 0.9 dl of ice cream. Calculate the depth of the cone. - RT 10

Area of right triangle is 17 cm^{2}and one of its cathethus is a=8 cm. Calculate perimeter of the triangle ABC. - Elevation

What must be the elevation of an observer in order that he may be able to see an object on the earth 814 km away? Assume the earth to be a smooth sphere with radius 6378.1 km. - XY triangle

Determine area of triangle given by line -7x+7y+63=0 and coordinate axes x and y. - Stairway

What angle rising stairway if step height in 17 cm and width 24 cm? - IS triangle

Calculate interior angles of the isosceles triangle with base 37 cm and legs 36 cm long. - Pine

How much of a mixed forest rangers want to cut down, if their head said: "We only cut down pine trees, which in our mixed forest 96%. After cut pine trees constitute 91% of all trees left." - Equator

Suppose that tourist went on foot over the Globe equator. How many meters more track made his hat on his head as the shoes on your feet? The radius of the earth is 6378 km and height of the tourist is 1.7 m. - Fertilizer

Meadow with an area of 1,500 square meters was fertilized with 12 kg of urea. Urea contains 45% nitrogen. How much nitrogen accounted per 1 m^{2}? - Spain vs USA

Spain lost to the US by 4 goals. In the match total fell 10 goals. How many goals gave the Spain and how the United States? - Bookshelve

Bookshelve with an original price of € 200 twice become cheaper. After the second discounted by 15% the price was € 149.60. Determine how much % become cheaper for the first time.

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