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

Liner regression, Liner Regression The calculations for our sample siz...

Liner Regression The calculations for our sample size n = 10 are described below. The linear regression model is y = a + bx Table: Distance x miles

Square the next consecutive integer find the lesser integer, The square of ...

The square of one integer is 55 less than the square of the next consecutive integer. Find the lesser integer. Let x = the lesser integer and let x + 1 = the greater integer. T

On income and return from shares, a company declares a semu annual dividend...

a company declares a semu annual dividend on 5%.a man has 400 shares of the company.if his annual income from the share is rs 1000 find the face value of each share?

Please help me solve these Problems step by step, What angle (to the neares...

What angle (to the nearest degree) corresponds to the cos 0.6 or what is cos-1(0.6)? (Note: Use Appendix I) What angle (to the nearest degree) corresponds to the sin 0.6 or what

Surface area and volume, a child prepares a poster to save energy on a squa...

a child prepares a poster to save energy on a square sheet whose each side measures 50 cm . At each corner she draws a quadrant of radius 5 cm and the centre of a circle of diamete

Which of the subsequent decimals is the greatest number, Which of the subse...

Which of the subsequent decimals is the greatest number? If you add zeros to the end of every of the numbers so that each number has 5 places after the decimal point, it is sim

What was the temperature at midnight, The temperature at 6 P.M. was 31°F. T...

The temperature at 6 P.M. was 31°F. Through midnight, it had dropped 40°F. What was the temperature at midnight? Visualize a number line. The drop from 31° to 0° is 31°. There

Personal assistance needed, I have an original finding on the subject of pr...

I have an original finding on the subject of prime distribution and would like expert help in my endeavors. I have written a paper describing everything in detail and demonstration

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