# Examples of area of plane shapes - page 14

1. Rectangle - sides 3 If in the rectangle ABCD we enlarge the side a by 5 cm and decrease the side b by 2 cm, the rectangle area will be reduced by 5 cm². When we decrease the length of the side a by 4 cm and and at the same time we increase the length of side b by 3 cm we incr
2. Hřiště Map scale is 1: 5000. The playground is rectangular and on the map has dimensions 10 cm and 5 cm What is area of playground in square meters in reality?
3. Rhombus A2p Rhombus area is 13 cm2 and its height is 5cm long . Determine a perimeter of this rhombus.
4. Tiler On what surface m2 tiler must lay 30 square tiles, each of which has a side 25 cm?
5. Trapezoid 15 Area of trapezoid is 266. What value is x if bases b1 is 2x-3, b2 is 2x+1 and height h is x+4
6. Inscribed circle Write the equation of a incircle of the triangle KLM if K [2,1], L [6,4], M [6,1].
7. The field The player crossed the field diagonally and walked the length of 250 m. Calculate the length of the field, circumference if one side of field 25 meters.
8. Rectangular field One dimension of the rectangular field is 56 m greater than second dimension. If each side of the rectangle increases by 10 m, increases the surface field is 1480 m2 . Determine dimencions of the field.
9. Pagans Elena cut out same circle-shaped pagans and put them on a rectangular sheet so that the neighboring pagans were touching each other and the pagans were touching the walls of the sheet on the edges. Each pagans occupied 28.26 cm2 of the bottom of the sheet.
10. Right triangle Right triangle legs has lengths 630 mm and 411 dm. Calculate the area of this triangle.
11. Diamond diagonals Calculate the diamond's diagonal lengths if its content is 156 cm2 and the side length is 13 cm.
12. Trapezium The area of trapezium is 35cm2 find its altitude if the bases are 6cm and 8cm.
13. Surveyor Calculate the area of ​​what may vary rectangular, if it focused by surveyor and found the dimensions 18 x 15 m while in each of the four joint points can be position deviation 25 cm?
14. Harvester Harvester has cutting width 4 m and harvested grain in the field, which is 87 meters wide. Harvester moves along the length of the field for six minutes, going back (without cutting) it takes half the time. Each turn at the end field take one minute. How m
15. Prism The base of a perpendicular triangular prism is a right triangle with legs 4.5 cm and 6 cm long. What is the surface of the prism, if its volume is 54 cubic centimeters?
16. CD disc A compact disc has a diameter of 11.8 cm. What is the surface area of the disc in square centimeters?
17. Regular triangular prism Calculate the surface area of body of regular triangular prism, when the length of its base edge is 6.5 cm and height 0.2 m.
18. Parallelogram ABCD The area of parallelogram ABCD is 440 cm2. Points M and N are the midpoints of the sides AB and BC. What is the area of a quadrilateral MBND?
19. Wall painting The wall is 5 meters wide and 2 meters high. Window in the wall has dimensions 2x1,8 meters. How many litera of color is needed to paint two-layer this walls, if the 1 m2 needs 1.1 liters of paint?
20. Strip From 5.9 cm wide strip should be cut rhombus with area 28 cm2. How long will be its side?

Do you have an interesting mathematical example that you can't solve it? Enter it, and we can try to solve it.

To this e-mail address, we will reply solution; solved examples are also published here. Please enter e-mail correctly and check whether you don't have a full mailbox.