# Expression of a variable from formula - problems - page 28

1. Hectoliters How deep is the pool if there are 2025 hectoliters of water and the bottom dimensions are a = 15 meters b = 7,5 meters and the water level is up to 9/10 (nine-tenths) of height.
2. Concentric circles There is given a circle K with a radius r = 8 cm. How large must a radius have a smaller concentric circle that divides the circle K into two parts with the same area?
3. Perimeter of a rectangle If the perimeter of a rectangle is 114 meters and the length is twice the width plus 6 meters, what are the length and width?
4. GP members The geometric sequence has 10 members. The last two members are 2 and -1. Which member is -1/16?
5. Expression Solve for a specified variable: P=a+4b+3c, for a
6. Twenty Twenty rabbits are put in 4 cells so that there are different number of rabbits in each cell contains at least 3 rabbits. What is the largest possible number of rabbits in one cell
7. Area to perimeter Calculate circle circumference if its area is 254.34cm2
8. The volume 2 The volume of a cube is 27 cubic meters. Find the height of the cube.
9. Rectangular trapezoid In a rectangular trapezoid ABCD with right angles at vertices A and D with sides a = 12cm, b = 13cm, c = 7cm. Find the angles beta and gamma and height v.
10. Algebra X+y=5, find xy (find the product of x and y if x+y = 5)
11. Ratio of volumes If the heights of two cylindrical drums are in the ratio 7:8 and their base radii are in the ratio 4:3. What is the ratio of their volumes?
12. Calculate 3 Calculate the cube volume whose edge is 3x-1,3x-1,3x-1
13. A rectangle A rectangle has an area of 36 cm2. What could the length and width of rectangle be?
14. Calculate 2 Calculate the largest angle of the triangle whose side are 5.2cm, 3.6cm, and 2.1cm
15. Find the 2 Find the term independent of x in the expansion of (4x3+1/2x)8
16. Expression with powers If x-1/x=5, find the value of x4+1/x4
17. Rectangular field A rectangular field has a diagonal of length 169m. If the length and width are in the ratio 12:5. Find the dimensions of the field, the perimeter of the field and the area of the field.
18. Pile of sand A large pile of sand has been dumped into a conical pile in a warehouse. The slant height of the pile is 20 feet. The diameter of the base of the sand pile is 31 feet. Find the volume of the pile of sand.
19. Thunderstorm The height of the pole before the storm is 10 m. After a storm when they come to check it they see that on the ground from the pole blows part of the column. Distance from the pole is 3 meters. At how high was the pole broken? (In fact, a rectangular tria
20. Brakes The braking efficiency of a passenger car is required to stop at 12.5 m at an initial speed of 40 km/h. What is the acceleration braking by brakes?

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