# Units - examples - page 87

1. Free fall How long does the stone fall freely into a depth of 80m? What speed will it hit the bottom of the abyss?
2. Quarters How many meters is a quarter of a kilometer? How many centimeters is a quarter of a meter, how many cents is a quarter of the euro?
3. ABCD AC= 40cm , angle DAB=38 , angle DCB=58 , angle DBC=90 , DB is perpendicular on AC , find BD and AD
4. Iron collecting Class 7A collected 3.2 tonnes of iron more than class 7B. Together they collected 6.4 tonnes of iron to the secondary raw material collection. How much did each class collect?
5. Surface of cubes Peter molded a cuboid 2 cm, 4cm, 9cm of plasticine. Then the plasticine split into two parts in a ratio 1:8. From each part made a cube. In what ratio are the surfaces of these cubes?
6. 3 cats 3 cats eat 3 mice in 3 days. How many mice will eat 10 cats in 10 days?
7. Solid cuboid A solid cuboid has a volume of 40 cm3. The cuboid has a total surface area of 100 cm squared. One edge of the cuboid has length 2 cm. Find the length of a diagonal of the cuboid. Give your answer correct to 3 sig. Fig.
8. Area of iso-trap Find the area of an isosceles trapezoid, if the lengths of its bases are 16 cm, and 30 cm, and the diagonals are perpendicular to each other.
9. Points on line segment Points P & Q belong to segment AB. If AB=a, AP = 2PQ = 2QB, find the distance: between point A and the midpoint of the segment QB.
10. Trapezium internal angles A trapezium where AB is parallel to CD, has angle A : angle D = 4 :5, angle B = 3x-15 and angle C = 4x+20. Find angle A, B, C and D.
11. Thunder and lightning There was a glimpse of the sky and we hear a thunder in 4.5 seconds. The light spreads at 300,000 kilometers per second, so we can assume the flash instantly without delay. However, the speed of the sound is much smaller in the air one third of a kilomete
12. Family 8 Father is 38 years old, daughter 12, son 14. How many years will father have as many years as his children together?
13. Photo enlarge Mark wants to enlarge a 4-inch by 6-inch photo so that it has a height of 15inches. Use a ratio table to determine the new width of the photo.
14. How far From the top of a lighthouse 145 ft above sea level, the angle of depression of a boat 29°. How far is the boat from the lighthouse?
15. Fridays Friday 13th is in 4 days. What day is today and what day it is?
16. Two cuboids Find the volume of cuboidal box whose one edge is: a) 1.4m and b) 2.1dm
17. Five pumps The water tank is filled with two pumps in 48 minutes. How long would it take to fill it with 5 same pumps?
18. Milk bill Mrs Tara buys 2 liters of milk daily. If 1 liter of milk cost \$0.27. What will be her milk bill for 30 days.
19. Soda A pack of 12 sodas cost 5.04. What is the unit rate in dollars per soda?
20. Bathroom 2 A bathroom is 2.4 meters long and 1.8 meters wide. How many square tiles 1 dm on each side are to be used to cover it?

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