Advertisements
Advertisements
प्रश्न
The areas of two circles are in the ratio 49 : 64. Find the ratio of their circumferences.
Advertisements
उत्तर
Given, the area of two circles are in the ratio 49 : 64
Area of a circle = πr2
Let area of the first circle = `pir_1^2`
And area of the second circle = `pir_2^2`
According to the question,
`49/64 = (pir_1^2)/(pir_2^2)`
⇒ `49/64 = r_1^2/r_2^2`
⇒ `(7)^2/(8)^2 = r_1^2/r_2^2`
⇒ `(7/8)^2 = (r_1/r_2)^2`
∴ r1 = 7 and r2 = 8
The ratio of circumferences of these two circles
= `(2pir_1)/(2pir_2)` ...[∵ Circumference of circle = 2πr]
= `r_1/r_2`
= `7/8`
Hence, required ratio is 7 : 8
APPEARS IN
संबंधित प्रश्न
The shape of the top surface of a table is a trapezium. Find its area if its parallel sides are 1 m and 1.2 m and perpendicular distance between them is 0.8 m.
Top surface of a raised platform is in the shape of a regular octagon as shown in the figure. Find the area of the octagonal surface.
Find the height of a trapezium, the sum of the lengths of whose bases (parallel sides) is 60 cm and whose area is 600 cm2.
Find the area of the field shown in Fig. 20.39 by dividing it into a square, a rectangle and a trapezium.
Find the area enclosed by each of the following figures [Fig. 20.49 (i)-(iii)] as the sum of the areas of a rectangle and a trapezium:
☐ PQRS is an isosceles trapezium l(PQ) = 7 cm. seg PM ⊥ seg SR, l(SM) = 3 cm, Distance between two parallel sides is 4 cm, find the area of ☐ PQRS.
The two parallel sides and the distance between them are in the ratio 3: 4: 2. If the area of the trapezium is 175 cm2, find its height.
Find the missing values.
| Height 'h' | Parallel side 'a` | Parallel side 'b` | Area |
| 16 cm | 15 cm | 360 sq.cm |
The perimeter of a trapezium is 52 cm and its each non-parallel side is equal to 10 cm with its height 8 cm. Its area is ______.
The area of a trapezium become 4 times if its height gets doubled.
