# Examples for 8th grade - page 86

- Wall diagonal

Calculate the length of wall diagonal of the cube whose surface is 384 cm square. - Desribed circle to rectangle

Rectangle with sides 6 cm and 4 cm was circumscribed circle. What part of the content of the circle determined by the circumscribed circle occupies a rectangle? Express in perctentages(%). - Candies

The price for 1 kg of more expensive candies is 125 CZK. The price for 1 kg of cheaper candy is 100 CZK. We mix two different mixtures of candy. A) The first mixture contains 2 kg more expensive and 0.5 kg cheaper candy. Calculate the price for 1 kg of t - Rhombus

If we increase the rhombus side by 2.4 cm; its perimeter is 20 cm. How long was the side of the rhombus? - Rainfall

The annual average rainfall in India was in Cherrapunji in the year 1981 26 461 mm. How many hectoliters of water fell on 1 m^{2}? Would fit this amount of water into a cube of three meters? - Blueberries

Miko and Anton have a total of 1,580 blueberries. Miko and Anton have them in the ratio 2: 3. Determine how much each of them has. - The cylinder base

The cylinder with a base of 8 dm^{2}has a volume of 120 liters. From a cylinder fully filled with water, 40 liters of water was removed. At what height from the bottom /with precision to dm/ is the water level? - 3 masons

3 masons received 7,700 CZK. The second half received 1/2 more than the first and third twice more than the second mason. How much they each got crowns? - Quadrangular pyramid

Calculate the surface area and volume of a regular quadrangular pyramid: sides of bases (bottom, top): a1 = 18 cm, a2 = 6cm angle α = 60 ° (Angle α is the angle between the side wall and the plane of the base.) S =? , V =? - Doubling

The message is spreading that each day has doubled the number of people who know about it. All know message for 20 days. How long known it eighth people? - Cows

Agricultural cooperative has increased the number of housed cows by 14% to 285 units. By how many cows increased agricultural cooperative the number of cows? - Jane class

When asked how many students are in class, Jane said, if we increase the number of students in our class by hundred % and then add half the number of students, we get 100. How many students are in Jane's class? - Diagonals in diamons/rhombus

Rhombus ABCD has side length AB = 4 cm and a length of one diagonal of 6.4 cm. Calculate the length of the other diagonal. - Regular n-gon

Which regular polygon have a radius of circumscribed circle r = 10 cm and the radius of inscribed circle p = 9.962 cm? - Map scale

On a 1:1000 scale map is a rectangular land of 4.2 cm and 5.8 cm. What is the area of this land in square meters? - Content area and percents

Determine what percentage is smaller cube surface, when the surface area of the wall decreases by 25%. - Volleyball

8 girls wants to play volleyball against boys. On the field at one time can be six players per team. How many initial teams of this girls may trainer to choose? - Tree trunk

From the tree trunk, the diameter at the narrower end is 28 cm, a beam of square cross-section is to be made. Calculate the longest side of the largest possible square cross-section. - Two sisters

Two sisters together have 54 CDs. 6/8 CDs has younger sister and is equal to 3/5 of CDs older sisters. How many CDs has each of the sisters? - Cube walls

Find the volume and surface area of the cube if the area of one wall is 40cm2.

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