Maths practice for 14 year olds - page 378 of 382

Number of problems found: 7626

Isosceles right triangle
Calculate the area of an isosceles right triangle whose perimeter is 810 cm.
Barrel of oil
The barrel of oil weighs 283 kg. When it molded 26% oil, it weighed 216 kg. What is the mass of the empty barrel?
Golden ratio
Divide the line of length 871 cm into two sections so that the ratio of shorter to greater is the same as the ratio of the greater section to the whole length of the line.
Magnification of the square
If the side of a square is increased, the area increases by 57%. By what percentage was the side increased?
The cyclist
A cyclist travelled from a village to a town. The first half of the journey was at 24 km/h. The second half, which was mostly downhill, was at 38 km/h. The entire journey took 94 minutes. Calculate the distance from the village to the town.
Circle and angle
What is the arc length of a circle with radius r = 432 dm corresponding to a central angle of 0.53 rad?
Widescreen monitor
Widescreen monitors and televisions have flooded the market. Calculate the screen area of an LCD monitor with a diagonal of 27 inches at a 4:3 aspect ratio and then at a 16:9 aspect ratio. Is buying a widescreen monitor with the same diagonal more advanta
Roller
The lateral surface area of a cylinder equals the area of one of its bases. The cylinder height is 23 dm. What is the radius of the base of the cylinder?
Cylinder - basics
A cylinder has a base radius r = 24 cm and height h = 62 cm. Calculate: a) The area of the base
Cylinder - A&V
A cylinder has a volume of 463. Its base has a radius of 4. What is the total surface area of the cylinder?
Similarity n-gon
6-gones ABCDEF and A'B'C'D'E'F' are similar. The area of 6-gon ABCDEF is S₁=248 m², and the diagonal length FA is 28 m. Calculate the area of the 6-gon A'B'C'D'E'F' if F'A' = 36 m.
Glass mosaic
How many dm² of glass is needed to produce 97 panes in the shape of a regular hexagon with a side length of 21 cm? Assume that 10% of the glass is wasted in cutting.
Rectangle - sides ratio
Calculate the area of a rectangle whose sides are in the ratio 2:16 and whose perimeter is 1289.
Railways - golden parachutes
This is an example more from political science, or even a fairy tale about carp who won't drain their pond. Let's look at the short work of the director of the Carp Railway Company: 18 months of quasi "work" as director reduction and elimination
Electronics: Resistors in parallel
Concerning calculating the resistance of the parallel combination of resistors: (1)/(R) = (1)/(R₁) + (1)/(R₂) Calculate the R, if R₁ = 17Ω a R₂ = 20Ω
Triangle angles
The angles α, β, and γ of triangle ABC are in the ratio 6:2:6. Calculate the size of each angle.
Tractors
Two tractors with different capacities are to plough a field. The first tractor can plough the entire field in 14 hours. The second tractor can plough the entire field 8 hours déle. How long does it take both tractors to plough the entire field working to
Bits, bytes
Calculate how many different numbers can be encoded in a 64-bit binary word.
Rectangle Anton
The difference between the length and width of a rectangle is 3. The length is 2 times greater than the width. Calculate the dimensions of the rectangle.
Morse alphabet
Calculate how many words of Morse code to create compiling dashes and dots in the words of one to piatich characters.

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