# Expression of a variable from formula - problems - page 24

1. Deviation of the lines Find the deviation of the lines AG, BH in the ABCDEFGH box-cuboid, if given | AB | = 3cm, | AD | = 2cm, | AE | = 4cm
2. A cylinder A cylinder 108 cm high has a circumference of 24 cm. A string makes exactly 6 complete turns around the cylinder while its two ends touch the cylinder's top and bottom. (forming a spiral around the cylinder). How long is the string in cm?
3. Find parameters Find parameters of the circle in the plane - coordinates of center and radius: ?
4. Girls The boys and girls in the class formed without the rest of the fives, 2 girls and 3 boys. There are 6 girls missing to create mixed pairs (1 boy and 1 girl). How many girls are in the classroom?
5. Final exam There are 5 learners in a class that has written a final exam Aleta scored 55% vera scored 36% and Sibusiso scored 88% if Thoko scored 71% and the class average was 63%. What was Davids score as a percentage?
6. Guppies Audrey has some guppies in a fish tank. The ration of the oranges guppies to silver guppies is 3:5. She has 12y oranges guppies. Write the number of silver guppies she has in terms of y
7. Spherical tank The tank of a water tower is a sphere of radius 35ft. If the tank is filled to one quarter of full, what is the height of the water?
8. Isosceles trapezium Calculate the area of an isosceles trapezium ABCD if a = 10cm, b = 5cm, c = 4cm.
9. Geometric progression In geometric progression, a1 = 7, q = 5. Find the condition for n to sum first n members is: sn≤217.
10. Pilot How high is the airplane's pilot to see 0.001 of Earth's surface?
11. Perimeter of base The circumference of the base of the rotating cylinder is same as its height. What is the diameter and height of this cylinder with volume 1 liter?
12. Calculate Calculate the length of a side of the equilateral triangle with an area of 50cm2.
13. Diagonals of pentagon Calculate the diagonal length of the regular pentagon: a) inscribed in a circle of radius 12dm; b) a circumscribed circle with a radius of 12dm.
14. KLMN trapezoid The KLMN trapezoid has bases KL 40cm and MN 16cm. On the KL base is point P. The segment NP divides the trapezoid into units with the same area. What is the distance of point P from point K?
15. Rectangle diagonal The rectangle, one side of which is 5 cm long, is divided by a 13 cm diagonal into two triangles. Calculate the area of one of these triangles in cm2.
16. 3d printer 3D printing ABS filament with diameter 1.75 mm has density 1.04 g/cm3. Find the length of m = 5 kg spool filament. (how to calculate length)
17. Meat loses Meat loses 18% of its weight by smoking. How much raw meat butcher used to manufacture 35 kilos of smoked?
18. Motorcyclist From Trutnov, the motorcyclist started at an average speed of 60km/hour. At 12.30hrs the passenger car was started at a speed of 80km/hour. How many hours and at what distance from Trutnov will car catch a motorcycle?
19. Square root 2 If the square root of 3m2 +22 and -x = 0, and x=7, what is m?
20. Cylinder height Calculate the height of the cylinder and its surface is 2500 dm2 and the bases have a diameter 5dm.

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