# Examples for 8th grade - page 51

- Holiday SMS

Kucera and Malek start from the holiday together. They agreed that if they be 100 km apart, will send a SMS. Kucera traveling at 60 km/h., Malek 90 km/h. They started at 14 hours PM. At what time they send a message? - Field with vegetables

Field planted with vegetables has shape of a rectangular isosceles triangle with leg length of 24 m. At the vertices of the triangle are positioned rotating sprinklers with a range of 12 m. How much of the field sprinkler doesn't irrigated? - School year

At the end of the school year has awarded 20% of the 250 children who attend school. Awat got 18% boys and 23% of girls. Determine how many boys and how many girls attend school. - Internal angles

One internal angle of the triangle JAR is 25 degrees. The difference is the size of the two other is 15°. Identify the size of these angles. - Uranium ore

Uranium ore contains 0.2% of pure uranium and pure uranium contains 0.07% of fissile uranium. How many grams of fissile uranium contains 2200 ton of uranium ore? - Triangle

Calculate the sides of the triangle if its area S = 630 and the second cathethus is shorter by 17. - ISO triangle

Calculate the area of an isosceles triangle KLM if the length of its sides are in the ratio k:l:m = 4:4:3 and has perimeter 128 mm. - Parcel

Both dimensions of the rectangular parcel were increased by 40%. By how many % has increased its acreage? - Cylinder - h2

Cylinder volume is 2.7 liters. Base area is 1 dm^{2.}Calculate the height of the cylinder. - Reservoir + water

Reservoir completely filled with water weighs 13 kg. After pouring off three quarters of the amount of water weights 4 kg. Calculate the weight and volume of the reservoir. - Quadrilateral

In the square ABCD point P is in the middle of the DC side and point Q in the middle pages AD. If the area of quadrilateral BQPC is 96 cm^{2,}what is the area of ABCD? - Diamond

Rhombus has side 23 cm and and one of diagonal 36 cm long. Calculate its area. - EQL triangle

Calculate inradius and circumradius of equilateral triangle with side a=100 cm. - Trapezoid ABCD v2

Trapezoid ABCD has length of bases in ratio 3:2. The area of riangle ACD is 956 dm^{2.}What is the area of trapezoid ABCD? - TV commercials

For the typical one-hour prime-time television slot, the number of minutes of commercials is 7/23 of the minutes of the actual program. Determine how many minutes of the program are shown in that one hour. - Trapezoid ABCD

Calculate the perimeter of trapezoid ABCD if we know the side c=25, b=16 which is also a height and side d=27. - Slope of the pool

Calculate slope (rise:run) of the bottom of swimming pool long 40 m. Water depth at beginning of pool is 1.15 m (for children) and depth at end is 1.92 m (for swimmers). Slope express as percentage and as angle in degrees. - Rectangles - sides

One side of the rectangle is 25 cm longer than second. Shortens longer side by 14 cm and extend shorter by 13 cm increases the area of the rectangle by 130 cm^{2.}What are the dimensions of the original rectangle? - Two wine

In 2:1 mix wine solution cost 4.1 USD. In 1:2 mix wine solution cost 4.5 USD. How much cost liter of each wine? - Lid

What is the weight of concrete cover (lid) to round shape well with a diameter 1.3 m, if the thickness of the cover is 15 cm? 1 m^{3}of concrete weighs 2190 kg.

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