Advertisements
Advertisements
प्रश्न
The area of a circle is given by the expression πx2 + 6πx + 9π. Find the radius of the circle.
उत्तर
We have,
Area of a circle = πx2 + 6πx + 9π = π(x2 + 6x + 9)
⇒ πr2 = π(x2 + 3x + 3x + 9) ...[∵ Area of a circle = πr2, where r is the radius]
⇒ πr2 = π[x(x + 3) + 3(x + 3)] = π(x + 3)(x + 3) = π(x + 3)2
⇒ πr2 = π(x + 3)2
On comapring both sides, r2 = (x + 3)2 ⇒ r = x + 3
Hence, the radius of circle is x + 3.
APPEARS IN
संबंधित प्रश्न
Use a suitable identity to get the following products.
(1.1m − 0.4) (1.1 m + 0.4)
Find the following squares by suing the identities.
`(2/3 m + 3/4 n)^2`
Using identities, evaluate 9982
Using a2 − b2 = (a + b) (a − b), find 12.12 − 7.92
Expand: (2a – 3b)2
Factorise the following using suitable identity
36m2 + 60m + 25
Factorise the following, using the identity a2 + 2ab + b2 = (a + b)2.
a2x2 + 2abx + b2
Factorise the following.
y2 + 18x + 65
If a2 + b2 = 74 and ab = 35, then find a + b.
Find the length of the side of the given square if area of the square is 625 square units and then find the value of x.
