# Examples of area of plane shapes - page 17

1. Equilateral triangle v3 Calculate the content of the colored gray part. Equilateral triangle has side length 8 cm. Arc centers are the vertices of a triangle.
2. Carpet What is the price of square carpet side length 3.25 m if one meter square cost 230 CZK?
3. Magic belt The magic rectangular belt has the property that whenever its owner wants something, the length of the belt is reduced to 1/2 and the width to 1/3. After three such wishes, the belt had a content area 4 cm2. What was its original length if the original wid
4. Playground Fencing square playground cost € 464; 1 meter cost € 19. What is the area of the playground?
5. Rectangle 3-4-5 The sides of the rectangle are in a ratio of 3:4. The length of the rectangle diagonal is 20 cm. Calculate the content of the rectangle.
6. Interesting property Plot a rectangular shape has the interesting property that circumference in meters and the area in square meters are the same numbers. What are the dimensions of the rectangle?
7. Rectangle The rectangle area is 182 dm2, its base is 14 dm. How long is the other side? Calculate its perimeter.
8. Annulus Calculate the area of two circles annulus k1 (S, 3 cm) and k2 (S, 5 cm).
9. Triangle ABC v2 Area of the triangle is 12 cm square. Angle ACB = 30º , AC = (x + 2) cm, BC = x cm. Calculate the value of x.
10. Math heart Stylized heart shape created from a square with side 5 cm and two semicircles over his sides. Calculate the content area and its circumference.
11. Concrete pedestal The carpenters made wooden mold on a concrete pedestal in the shape of a cube with edge 2 meter long. What is the area in which the concrete touches wooden molds? (No lid or bottom)
12. The farmer The farmer would like to first seed his small field. The required amount depends on the seed area. Field has a triangular shape. The farmer had fenced field, so he knows the lengths of the sides: 119, 111 and 90 meters. Find a suitable way to determine th
13. Painting The room is long 50 meters and wide 60dm and 300 cm high. Calculate how much it will cost painting if area of windows and doors is 15% of the total area. One square meter cost 50cents.
14. Circle - easy 2 The circle has a radius 6 cm. Calculate:
15. Quatrefoil Calculate area of the quatrefoil which is inscribed in a square with side 6 cm.
16. Pentagon Calculate the length of side, circumference and area of a regular pentagon, which is inscribed in a circle with radius r = 6 cm.
17. Glass aquarium How many m2 of glass are needed to produce aquarium with bottom dimensions of 70 cm x 40 cm and 50 cm high?
18. The cube The surface of the cube is 150 square centimeters. Calculate: a- the content of its walls b - the length of its edges
19. Four circles 1) Calculate the circle radius if its area is 400 cm square 2) Calculate the radius of the circle whose circumference is 400 cm. 3) Calculate circle circumference if its area is 400 cm square 4) Calculate the circle's area if perimeter 400 cm.
20. Octagonal mat Octagonal mat formed from a square plate with a side of 40 cm so that every corner cut the isosceles triangle with leg 3.6 cm. What is the content area of one mat?

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