# Examples for 7th grade (seventh) - page 56

- Circle - simple

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

Identify unknown number which 1/5 is 40 greater than one tenth of that number. - 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? - Trio 2

Decide whether trio of numbers is the side of a right triangle: 26,24,10. - Wood lumber

Wooden lumber is 4 m long and has a cross section square with side 15 cm. Calculate: a) the volume of lumber b) the weight of the lumber if 1 m^{3}weighs 790 kg - 15 number

What number is smaller (greater) by 15 than its half? - Tank

How many minutes does it take to fill the tank to 25 cubic meters of water filled 150hl per hour? - 2d shape

Calculate the content of a shape in which an arbitrary point is not more than 3 cm from the segment AB. The length of the segment AB is 5 cm. - Sales off

Calculate what was the original price of the good, if the price after discount 25% and the subsequent rise of 20% is 400 USD. - Cube

How many times increases the surface area of a cube with edge 23.4 cm if the length of the edge doubled? - Plot

The plot on which Mr. Kalous is to build a house has the shape of a rectangle. On a 1: 500 scale, its dimensions are 7cm and 5.5cm. Find out the dimensions of the plot. Calculate the parcel size. - Troops

If the general sorts troops into the crowd by nine left 6. How many soldiers has regiment if we know that they are less than 300? - Log

Worker cut his thick log to 6 pieces for 30 min. How long he cut log to 12 pieces? - Addends

Number 118 divide into two addends, so first addend is 69 greater than 75% of the second addend. - Potatoes

Daniela and Michael would jointly dug potatoes for 7.5 hours. But if Daniela was working alone she would take 2.5 hours more as if he were working with Michael. Determine how much for the work done by Michael himself and how much Daniela herself. - Car model

Car model is 52 mm long and the real car is 4524 mm long. What was the scale of model car? - Megapascals

What is the area of crosssection of the piston, if the force of 300 kN produces a pressure of 5 MPa? - Assistant

Assistant rewrote 15% of the entire manuscript in 12 hours. How many hours must still write to rewrite the rest of the manuscript? - Z7-I-4 stars 4949

Write instead of stars digits so the next write of product of the two numbers to be valid: ∗ ∗ ∗ · ∗ ∗ ∗ ∗ ∗ ∗ ∗ 4 9 4 9 ∗ ∗ ∗ ∗ ∗ ∗ 4 ∗ ∗ - Cube edge

Determine the edges of the cube when the surface is equal to 37.5 cm square.

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