# Examples for 7th grade (seventh)

1. Square glass What is the area of the square window glass with the side 4 dm? Do you know how many cm2 is it?
2. Rhumbline Find circumference and area of the rhumbline ABCD if the short side AD of which has a length of 5 cm, and the heel of the height from D leading to the AB side divides the AB side into two sections of 3 cm and 4 cm.
3. Canister Gasoline is stored in a cuboid canister having dimensions 44.5 cm, 30 cm, 16 cm. What is the total weight of a full canister when one cubic meter of gasoline weighs 710 kg and the weight of empty canister is 1.5 kg?
4. Equation with x Solve the following equation: 2x- (8x + 1) - (x + 2) / 5 = 9
5. Charles Bridge Charles Bridge was 15 times older than Frantův bridge from 1900 in 1931. How old is the Charles Bridge?
6. Proportion write the following proportion 8 is to 64 as to 2 is to x
7. Broken tree The tree is broken at 4 meters above the ground and the top of the tree touches the ground at a distance of 5 from the trunk. Calculate the original height of the tree.
8. Hall Rectangular hall will have pave by square tiles with a side length 15 cm. The hall has length 18 meters and width 3 m. How many tiles need to buy if 2 percent of the amount is disrupted during the work?
9. Class In a class are 32 pupils. Of these are 8 boys. What percentage of girls are in the class?
10. Sunflower Field The trapezoidal sunflower field is located between two parallel paths which are spaced 230 meters apart. The lengths of the parallel sides of the field are 255 m and 274 m. How many tons of sunflower will come from this field if the hectare yield is 2.25
11. Rectangular triangle PQR In the rectangular triangle PQR, the PQ leg is divided by the X point into two segments of which longer is 25cm long. The second leg PR has a length 16 cm. The length of the RX is 20 cm. Calculate the length p of side RQ. The result is round to 2 decima
12. Grandmother Grandmother wants to give the candies to grandchildren that when she gives 5 candy everyone 3 missing and when she gives 4 candies 3 is surplus. How many grandchildren has grandmother and how many candies has?
13. Elevator The panel house has ten over-ground floors and four underground. The lift goes from the ground floor to 2nd floors, then goes down to 3rd underground floors, then 9 floors up and finally 4 floors down. To what story elevator come? How many floors did it c
14. Cost reduction Windbreaker cost after discounted SKK 1275, which were 3/4 of original price. How many SKK originally cost windbreaker? How many SKK was cost reduction?
15. Cuboid - edges The cuboid has dimensions in ratio 4: 3: 5, the shortest edge is 12 cm long. Find: (A) the lengths of the remaining edges, (B) the surface of the cuboid, (C) the volume of the cuboid
16. Five pumps Three same pumps fill the tank with 50400 liters of diesel in 7 hours. How many liters of diesel will it take in 4 hours if we add two more of the same pumps and pump them the same way? How much more (or less) will they get if we add 2 of the same pumps
17. Rectangle from string String 12m. Make rectangle when one side is two times longer than its width.
18. Sputnik The first Earth satellite was flying at speed 8000 m/s. At that rate he circled the earth in 82 minutes. Jet flies at an average speed 800 km/h. How long would it take circle the earth round?
19. Cylindrical tank Cylindrical tank holds 600hl water and is deep 2.5 m. Calculate the diameter of the cylinder. What is the diameter of a tree around which is 3m 9dm 7cm long rope wrapped? How big is its cross-sectional area?