Examples for 8th grade - page 16
The boys from scout group traveled 3 days distance 105 km. Every day walked 1.3 km less than the previous day. How many kilometers scouts walked in the first day?
Cyclist who rides at an average speed 17 km/h travels trip distance 14 min before the cyclist who rides at an average speed 15 km/h. What is the length of this cyclist trip(distance in km)?
- Square grid
Square grid consists of a square with sides of length 1 cm. Draw in it at least three different patterns such that each had a content of 6 cm2 and circumference 12 cm and that their sides is in square grid.
- Perimeter and legs
Determine the perimeter of a right triangle if the length of one leg is 75% length of the second leg and its content area is 24 cm2.
- Triangular pyramid
Calculate the volume and surface area of a regular triangular pyramid whose height is equal to the length of the base edges 10 cm.
- Right triangle
Calculate the missing side b and interior angles, perimeter and area of a right triangle if a=10 cm and hypotenuse c = 16 cm.
- Magnification of the square
If we increase the square side, increase the content of the 42 %. About what percentage was increased his sides?
The perimeter of a circular sector with an angle 2 rad is 53 cm. Determine the radius of the circle from which the sector comes.
- EQL triangle
Calculate inradius and circumradius of equilateral triangle with side a=100 cm.
Truck went for 5 hours and 21 minutes. If truck increase speed by 19 km/h, went same distance in 2.9 hours. Calculate this distance.
An oil tanker can be emptied by the first pump in 4.4 hours. Second pump can empty an tanker in 7.8 hours. If the first pump started at 8:00 and second 1.4 hour later, at what time will the tanker be empty?
- Cube wall
Surface of first cube wall his 361 cm2. Second cube area is 30% of the surface of the first cube. Determine the length of the edge of the second cube (x).
Calculate the volume of a cuboid ABCDEFGH if |AB| = 11 cm, |BC| = 8 cm and the angle ∠CDG = 29.4°
- Cone and the ratio
Rotational cone has a height 28 cm and the ratio of the base surface to lateral surface is 4: 7. Calculate a surface of the base and the lateral surface.
- Election mathematics
In elections, 6 political parties received this shares of voters: strana A 69.4 %strana B 11.2 %strana C 10.2 %strana D 7.6 %strana E 1.6 % Calculate what the shares acquired in the parliament, if a quorum is 5%.
- Cardboard box
We want to make a cardboard box shaped quadrangular prism with rhombic base. Rhombus has a side of 5 cm and 8 cm one diagonal long. The height of the box to be 12 cm. The box will be open at the top. How many square centimeters cardboard we need, if we cal
- Hexagon - MO
The picture shows the ABCD square, the EFGD square and the HIJD rectangle. Points J and G lie on the side CD and is true |DJ|
- Sphere A2V
Surface of the sphere is 306 m2. What is its volume?
Between the two ports on the river is going steamship. The journey there and back takes 14:49. Downstream steamship traveling at 21 km/h, upstream 9 km/h. What is the distance between the ports?
- MO - triangles
On the AB and AC sides of the triangle ABC lies successive points E and F, on segment EF lie point D. The EF and BC lines are parallel and is true this ratio FD:DE = AE:EB = 2:1. The area of ABC triangle is 27 hectares and line segments EF, AD, and DB se