# Grade - examples - page 133

- 30-gon

At a regular 30-gon the radius of the inscribed circle is 15cm. Find the "a" side size, circle radius "R", circumference, and content area. - Circle from string

Martin has a long 628 mm string . He makes circle from it. Calculate the radius of the circle. - Disc

Circumference of the disk is 78.5 cm. What is the circumference of the circular arc of 32° on the disc? - Coins

Denis and Zdeno together have 97 coins. If Denis had 4 coins less than he has now, the number of the coins would be in the ratio 14: 17. Determine the number of coins owned by Denis and Zdeno. - Fuel economy

How many kilometers is sufficient petrol in the cylinder fuel tank with a diameter 40 cm and the base of tank length 1 m, when it is filled to 60% and if the car consume 15 liters per 100 km? - Charles Bridge

Charles Bridge was 15 times older than Frantův bridge from 1900 in 1931. How old is the Charles Bridge? - Perpetrator

The perpetrator is a number that is smaller than the number 80. It is a multiple of five and it is odd. If we added up the tens and ones of this number we get number 8. - Decide

The rectangle is divided into seven fields. On each box is to write just one of the numbers 1, 2 and 3. Mirek argue that it can be done so that the sum of the two numbers written next to each other was always different. Zuzana (Susan) instead argue that. - Percent

Calculate how many % is the number 26.25 less than the number 105. - Roses and tulips

At the florist are 50 tulips and 5 times less roses. How many flowers are in flower shop? - Cube surface area

The surface of the cube was originally 216 centimeters square. The surface of the cube has shrunk from 216 to 54 centimeters sq. Calculate how much percent the edge of the cube has decreased. - Percentage - fractions

About what percentage we must increase number 1/6 to get number 1/3? - Pharmacy

The pharmacy add to 3 liters of 95-percent alcohol 5 liters of 38.04 percent alcohol. How many percent pharmacy got? - Tank

To cuboid tank whose bottom has dimensions of 9 m and 15 m were flow 1080 hectoliters of water. This was filled 40% of the tank volume. Calculate the depth of the tank. - Unknown number 7

Calculate unknown number whose 12th power when divided by the 9th power get a number 27 times greater than the unknown number. Determine the unknown number. - Circle - simple

Calculate the area of a circle in dm^{2}, if its circumference is 31.4 cm. - Infinite decimal

Imagine the infinite decimal number 0.99999999 .. ... ... ... That is a decimal and her endless serie of nines. Determine how much this number is less than the number 1. Thank you in advance. - Unknown number

Identify unknown number which 1/5 is 40 greater than one tenth of that number. - Cylinder surface area

Volume of a cylinder whose height is equal to the radius of the base is 678.5 dm^{3}. Calculate its surface area. - Common cylinder

I've quite common example of a rotary cylinder. Known: S1 = 1 m^{2}, r = 0.1 m Calculate : v =? V =? You can verify the results?

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