Find the area enclosed between two concentric circles, Mathematics

Assignment Help:

Find the area enclosed between two concentric circles of radii 3.5cm, 7cm. A third  concentric circle is drawn outside the 7cm circle so that the area enclosed between it and the 7cm circle is same as that between two inner circles. Find the radius of the third circle                                                                                                             (Ans: 115.5 cm 2   r = √343 / 2 )

757_circle14.png

Ans:    Area between first two circles = Π x 72 - Π x 3.52

= 49 Π - 12.25 Π -------------(1)

Area between next two circles = Π r2 - Π x 72

= Π r2 - 49 Π -----------------(2)

(1) & (2) are equal

49 Π - 12.25 Π = Π r2 - 49 Π

Π r2 = 49 Π + 49 Π - 12.25 Π

∴ r2 = 98 - 12.25 = 85.75

r2 = 8575/100 = 343/4

r =  √343/2 cm.


Related Discussions:- Find the area enclosed between two concentric circles

#tiword problem proportions, The scale of a map is 0.5 in 25mi the actua...

The scale of a map is 0.5 in 25mi the actual distance between two cities is 725mi write a proportion that represents the relationship how far apart will the cities be on the map

Example of exponential smoothing, Example of Exponential Smoothing ...

Example of Exponential Smoothing By using the previous example and smoothing constant 0.3 generate monthly forecasts Months Sales Forecast

Example of graphing equations, Example of Graphing Equations: Example...

Example of Graphing Equations: Example: By using the above figure, find out the distance traveled if the average speed is 20 mph and the time traveled is 40 minutes. T

Percent of a number, Pay $40 for plan offered for $30 for plan what percent...

Pay $40 for plan offered for $30 for plan what percentage of savings

Sciencetific notations, how would you answer a question like this on here ...

how would you answer a question like this on here (8x10^5)

Area related to circle, If ABCD isaa square of side 6 cm find area of shad...

If ABCD isaa square of side 6 cm find area of shaded region

Times fractons, In a garden, 1/8 of the flowers are tulips. 1/4 of the tuli...

In a garden, 1/8 of the flowers are tulips. 1/4 of the tulips are red. What fraction of the flowers in the garden are red tulips?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd