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

Arithmetico geometric progression, find the sum of the following series upt...

find the sum of the following series upto n terms: 1*2+2*4+3*8+4*16+.....

Example of addition, Example 1 Add 4x 4 + 3x 3 - ...

Example 1 Add 4x 4 + 3x 3 - x 2 + x + 6 and -7x 4 - 3x 3 + 8x 2 + 8x - 4 We write them one below the other as shown below.

Nonhomogeneous systems, We now require addressing nonhomogeneous systems in...

We now require addressing nonhomogeneous systems in brief. Both of the methods which we looked at back in the second order differential equations section can also be used now.  Sin

Find the equation of circle concentric – coordinate geometry, 1. A point P(...

1. A point P(a,b) becomes (3,c) after reflection in x - axis, and (d,6) after reflection in the origin. Show that a = 3, b = - 6, c = 6, d = 2 2. If the pair of lines ax² + 2pxy

Word problem time vs desent, altitude 35000 @ 9:30 9;42 alt 17500 increase...

altitude 35000 @ 9:30 9;42 alt 17500 increase speed by factor of 3 level out at 2500= how much time will it take

Fact of the wronskian method, Given two functions f(x) and g(x) which are d...

Given two functions f(x) and g(x) which are differentiable on some interval I  (1) If W (f,g) (x 0 ) ≠ 0 for some x 0 in I, so f(x) and g(x) are linearly independent on the int

Problem solving involving quadratic equations, a painting is 20 cm wider th...

a painting is 20 cm wider than its height. its area is 2400 centimeter squared. find its lenght and width

Number theory, show that all primes except 2, are of the form 4n-1 or 4n+1...

show that all primes except 2, are of the form 4n-1 or 4n+1.

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