Examples for 8th grade - page 7
Gift box has rectangular shape with dimensions of 3×3×5 cm. Martin wants to cover with square paper with sides of 10 cm. How much paper left him?
- Two workers
Two workers together execute some work in 10 days. The first worker would have done himself in 20 days. How many days would have done himself a second worker?
The first tributary fill pool with water in 15 hours. The second tributary fill pool in 10 hours. For how many hours the pool is filled with both tributaries?
The tale of the Seven Ravens were seven brothers, each of whom was born exactly 1.5 years after the previous one. When the eldest of the brothers was 4-times older than the youngest, mother all curse. How old was seven ravens brothers when their mother cur
What acreage has a rectangular plot whose diagonal is 34 meters long and one side has a length of 16 meters. ?
- Katy MO
Kate draw triangle ABC. Middle of AB have mark as X and the center of the side AC as Y. On the side BC wants to find the point Z such that the content area of a 4gon AXZY was greatest. What part of the triangle ABC can maximally occupy 4-gon AXZY?
- Area of RT
Calculate the area of a right triangle which hypotenuse has length 20 and one hypotenuse segment has lenght 15.
Three copiers will do the same in an hour k copies. How many copies would be done in an hour by four such copiers? ?
- Octahedron - sum
On each wall of a regular octahedron is written one of the numbers 1, 2, 3, 4, 5, 6, 7 and 8, wherein on different sides are different numbers. For each wall John make the sum of the numbers written of three adjacent walls. Thus got eight sums, which also.
Boys run kite on a cable of 86 meters long. What is the kite altitude, if the angle from the horizontal plane is 77°?
Cube, which consists of 27 small cubes with edge 3 dm has volume:
Circle arc corresponding to angle is 193° is 23 dm long. What is the length of the entire circle?
From the cube of edge 52 cm was lathed maximum cylinder. What percentage of the cube is left as waste after lathed?
- Internal angles
The ABCD is an isosceles trapezoid, which holds: |AB| = 2 |BC| = 2 |CD| = 2 |DA|: On its side BC is a K point such that |BK| = 2 |KC|, on its side CD is the point L such that |CL| = 2 |LD|, and on its side DA the point M is such that | DM | = 2 |MA|. Dete
- Shadow and light
Nine meters height poplar tree has a shadow 16.2 meters long. How long shadow have at the same time Joe if he is 1,4m tall?
If the product twice price cut by 20%, what percentage was price cut in total?
Conduit has a cross section 492 mm. Maybe put it into 5 conductors with a cross section S2 $mm2?
- Tetrahedral pyramid
What is the surface of a regular tetrahedral (four-sided) pyramid if the base edge a=23 and height v=8?
The lorry was loaded with 27 boxes of 24 kg. How many boxes with weight 36 kg can be loaded, if total load must be same?
How many times a day hands on a clock overlap?