# Examples of area of plane shapes - page 11

1. Garden
Rectangular garden has a length 99 m and width 84 m. Calculate how many m2 will decrease its area if land by ornamental fence with width 30 cm.
2. Trapezium
Determine the height of the trapezium ABCD, which has area 77.5 cm2 and base lengths 16 cm and 15 cm.
3. Annulus
Two concentric circles form an annulus of width 10 cm. The radius of the smaller circle is 20 cm. Calculate the content area of annulus.
4. Logs
The log has diameter 30 cm. What's largest beam with a rectangular cross-section can carve from it?
5. Rotary cylinder
The rotating cylinder has a surface area 69.08 cm2. The area of the shell is 62.8 cm 2. What is the diameter of the cylinder?
6. The hall
The hall had a rectangular ground plan one dimension 20 m longer than the other. After rebuilding the length of the hall declined by 5 m and the width has increased by 10 m. Floor area increased by 300 m2. What were the original dimensions of the hall?
7. Rectangle - sides
What is the perimeter of a rectangle with area 266 cm2 if length of the shorter side is 5 cm shorter than the length of the longer side?
8. Parallelogram - side
Calculate the length of the side of a parallelogram whose area is 175 dm2 and height to that side is 24.2 dm long.
9. 7 triangle
The triangle area is 26.7 cm2. Determine the side length l if appropriate height hl = 45.3 cm.
10. Glass
Peter broke the window glass with size 110 cm and 90 cm. 1 square meter of glass costs 11 USD. How much money is need to pay for a new glass?
11. Acreage
What acreage has a rectangular plot whose diagonal is 34 meters long and one side has a length of 16 meters. ?
12. Hop-garden
The length of the rectangular hop garden Mr. Smith increased by 25% and its width by 30%. What is the percentage change in area of hop garden?
13. Window
Peter demolish box hole in the wall for window frame 147×51 cm. When they came masters fitted frame and window will be found that glass is 13.3 cm from the hole in each direction. Calculate how much percent less light enters the window than hole?
14. 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?
15. Parallelogram +ľ
| AB | = 76cm, | BC | = 44cm, angle BAD = 30 °. Find the area of the parallelogram.
16. Square plate
From a square metal plate with a side long 6dm were cut two identical rectangular openings with dimensions of 2.5 dm and 2 dm. Calculate the remainder of the square plate.
17. Annulus
The radius of the larger circle is 8cm, the radius of smaller is 5cm. Calculate the contents of the annulus.
18. Percentage of waste
In a square plate with side 75 cm we cut 4 same circles. Calculate the percentage of waste.
19. Rectangle vs square
One side of the rectangle is 1 cm shorter than the side of the square, the second side is 3 cm longer than the side of the square. Square and rectangle have the same content. Calculate the length of the sides of a square and a rectangle.
20. 6 regular polygon
It is given 6 side regular polygon whose side is 5 cm. Calculate its content area. Compare how many more cm2 (square centimeters) has a circle in which is inscribed the 6-gon.

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