Examples for 8th grade - page 54
The volume of tetrahedral prism is 2.43 m3. Base of prism is a parallelogram in which a side 2,5dm and height ha = 18cm. Calculate the height of the prism.
- Rhombus A2p
Rhombus area is 13 cm2 and its height is 5cm long . Determine a perimeter of this rhombus.
Wjat height reach water level in the tray shaped a cuboid, if it is 420 liters of water and bottom dimensions are 120 cm and 70 cm.
- Heating plant
Workers dump imported coke at heating plant. On the first day used half of the amount, the second day three quarters the rest and on the third day left 120 tons. How much coke they dump at heating plant?
- Two cars
From the town A to town B started two cars. The first at 7:00 at average speed 60 km per hour, the second at 10:00 at average speed 100 km per hour. The first car will not stay in B, and on the way back meet the second car at half way from A to B. At what.
How many square tiles with the content 121 cm2 has to be ordered for the paving of the square room with a side length of 2.75 meters?
- 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.
How long distance will travel a large (minute) hand on the clock for 39 minutes, if its length is 33 cm?
I have bevel in the ratio 1:6. What is the angle and how do I calculate it?
Half a kilogram of pork and three-quarters of a kilogram of beef cost total 6.6 USD. One quarter of a kilogram of beef and 1 kilogram of pork cost 6.3 USD. Determine the price of 1 kg of each type of meat.
- Car consumption
The car has consumption 6.9 l/100 km. How much money will it cost ride 6.9 km in long if diesel price is 1.61 USD/l?
- Hexagon 5
The distance of parallel sides of regular hexagonal is 81 cm. Calculate the length of the radius of the circle described to this hexagon.
Solve the inequation: 5k - (7k - 1)≤ 2/5 . (5-k)-2
- EQL triangle
Calculate inradius and circumradius of equilateral triangle with side a=100 cm.
Flowerbed has the shape of an isosceles obtuse triangle. Arm has a size 6.1 meters and an angle opposite to the base size is 93°. What is the distance from the base to opposite vertex?
- 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.
- Against each other
From two points A, B distant 45 km at the same time started two cars against each other at speeds 81 km/h and 67 km/h. How long does cars meet and what distance passes each of them?
- Map - climb
On the map of High Tatras in scale 1:25000 are cable car stations in the Tatranska Lomnica and in the Skalnate Pleso with distance 156 mm. Altitude of this stations are 944 m and 1755 m. What is average angle of climb of this cable car track?
- n-gon II
What is the side length of the regular 9-gon circumscribed circle of radius 13 cm?
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 m3 of concrete weighs 2190 kg.