Examples for 8th grade - page 69
- Garden pond
Concrete garden pond has bottom shape of a semicircle with a diameter 1.1 m and is 47 cm deep. Daddy wants make it surface. How many liters of water is in pond if watel level is 22 cm?
- Mystery of stereometrie
Two regular tetrahedrons have surfaces 48 cm2 and 108 cm2. In what ratio is their volumes? Write as a fraction and as a decimal rounded to 4 decimal places.
In the newly built park will be permanently placed a rotating sprayer irrigation of lawns. Determine the largest radius of the circle which can irrigate by sprayer P so not to spray park visitors on line AB. Distance AB = 55 m, AP = 36 m and BP = 28 m.
- Total displacement
Calculate total displacement of the 12-cylinder engine with the diameter of the piston bore B = 6.8 cm and stroke S=2 cm of the piston. Help: the crankshaft makes one revolution while the piston moves from the top of the cylinder to the bottom and back t
- Slope form
Find the equation of a line given the point X(10, -2) and slope -1.2. Arrange your answer in the form y = ax + b, where a, b are the constants.
- Cuboid diagonal
Calculate the volume and surface area of the cuboid ABCDEFGH, which sides abc has dimensions in the ratio of 7:10:8 and if you know that the wall diagonal AC is 21 cm and angle between AC and the body diagonal AG is 40 degrees.
We have three cups. In the cups we had fluid and boredom we started to shed. 1 We shed one-third of the fluid from the second glass into the first and third. 2 Then we shed one quarter cup of liquid from the first to the second and to the third. 3 Then
Calculate volume and surface area of the cone with diameter of the base d = 12 cm and side of cone with the base has angle 41°47'59″.
If the segment of the line y = -8x +4 that lies in quadrant I is rotated about the y-axis, a cone is formed. What is the volume of the cone?
Area of the side of two cylinders is same rectangle of 45 cm × 32 cm. Which cylinder has a larger volume and by how much?
- Trains for people
It is said that the train is synonymous to delay. Calculate the average speed of travel by train long 50 km, with regular train leave at 6:05 and arrive at 7:20, but train is late and has departure at 9:52 and arrive at 11:05.
- Square 2
Points D[9,-1] and B[3,3] are opposed vertices of the square ABCD. Calculate area of the square ABCD.
One cube is inscribed sphere and the other one described. Calculate difference of volumes of cubes, if the difference of surfaces in 137 cm2.
- Chord MN
Chord MN of circle has distance from the center circle S 118 cm. Angle MSN is 41°. Determine the radius of the circle.
- Carbon dioxide
Calculate how many grams of oxygen are in 126 g of carbon dioxide CO2. Relative atomic mass of oxygen is 16 and of carbon is 12.
- Extreme temperatures
USA hit extreme heat wave. Calculate percentage of the air temperature change from normal summer temperature 24 °C to 37 °C.
- Widescreen monitor
Computer business hit by a wave of widescreen monitors and televisions. Calculate the area of the LCD monitor with a diagonal size 17 inches at ratio 4:3 and then 16:9 aspect ratio. Is buying widescreen monitors with same diagonal more advantageous tha
- Discounts on rail (ZSSK)
The railway company ZSSK offers a discount of 40% (JUNIOR RAILPLUS EURO
- Cone in cube
The cube is inscribed cone. Determine the ratio of the volume of cone and cube. The ratio express as a decimal number and as percentage.
- Triangle SAA
The triangle has one side long 34 m and its two internal angles is 60°. Calculate the perimeter and area of the triangle.