What is the radius of a circular field whose area is equal to the sum of the areas of three smaller circular fields of radii 8 m, 9 m and 12 m, respectively?
Answer & explanation
Correct answer: option 4
We know that,
Area of a circle = πr2
Radii of three smaller circular fields are 8 m, 9 m, and 12 m.
Let the radius of the larger circular field be r
So, The total area = Sum of all the other areas
= πr2 = π(82) + π(92) + π(122)
= πr2 = π(64) + π(81) + π(144)
= πr2 = π(289)
= r2 = 289
= r = 17 m