Advertisements
Advertisements
प्रश्न
An ant is moving around a few food pieces of different shapes scattered on the floor. For which food − piece would the ant have to take a longer round? Remember, circumference of a circle can be obtained by using the expression c = 2πr, where r is the radius of the circle.
Advertisements
उत्तर
a) Radius (r) of semi-circular part = `(2.8/2)` cm = 1.4 cm
Perimeter of the given figure = 2.8 cm + πr
= 2.8 cm + `(22/7 xx 1.4)` cm
= 2.8 cm + 4.4 cm
= 7.2 cm
b) Radius (r) of semi-circular part = `(2.8/2)` cm = 1.4 cm
Perimeter of the given figure = 1.5 cm + 2.8 cm + 1.5 cm +π (1.4 cm)
= 5.8 cm + `22/7` (1.4 cm)
= 5.8 cm + 4.4 cm
= 10.2 cm
c) Radius (r) of semi-circular part = `(2.8/2)` cm = 1.4 cm
Perimeter of the figure(c) = 2 cm + πr + 2 cm
= `4 cm + 22/7 xx (1.4 cm)`
= 4 cm + 4.4 cm
= 8.4 cm
Thus, the ant will have to take a longer round for the food-piece (b), because the perimeter of the figure given in alternative (b) is the greatest among all.
संबंधित प्रश्न
The shape of a garden is rectangular in the middle and semi circular at the ends as shown in the diagram. Find the area and the perimeter of the garden [Length of rectangle is 20 − (3.5 + 3.5) metres]
A flooring tile has the shape of a parallelogram whose base is 24 cm and the corresponding height is 10 cm. How many such tiles are required to cover a floor of area 1080 m2? (If required you can split the tiles in whatever way you want to fill up the corners).
A plot is in the form of a rectangle ABCD having semi-circle on BC as shown in Fig. 20.23. If AB = 60 m and BC = 28 m, find the area of the plot.
The inside perimeter of a running track (shown in Fig. 20.24) is 400 m. The length of each of the straight portion is 90 m and the ends are semi-circles. If track is everywhere 14 m wide, find the area of the track. Also, find the length of the outer running track.
The length and the breadth of a rectangular plot are 135 m and 65 m. Find, its perimeter and the cost of fencing it at the rate of ₹60 per m.
The length and breadth of the rectangular piece of land area in the ratio of 5 : 3. If the total cost of fencing it at the rate of ₹48 per metre is ₹19,200, find its length and breadth.
The length of an aluminium strip is 40 cm. If the lengths in cm are measured in natural numbers, write the measurement of all the possible rectangular frames which can be made out of it. (For example, a rectangular frame with 15 cm length and 5 cm breadth can be made from this strip.)
Which branch of mathematics deals with the measurement of length, area, volume, and surface area of geometric figures?
What is the part of the plane enclosed by a closed figure known as?
The interior of the rectangle, along with its boundary, is called the:
