Explanation

Sum of interior angles = (n − 2) × 180°

Given sum = 1260°  

So (n − 2) × 180 = 1260  

n − 2 = 1260 / 180 = 7  

n = 7 + 2 = 9

9 sides = nonagon

Last verified on 09-06-2026

Explanation

Surface area = 4πr², Volume = 4/3πr³.  

Surface area is just derivative of volume w.r.t r.

2πr is circumference of a circle, not volume at all.

Last verified on 07-06-2026

Explanation

Circumference C = 2πr

Given: C = 44 cm, π = 22/7

So r = C / (2π) = 44 / (2 × 22/7)  

= 44 / (44/7) = 44 × 7/44 = 7 cm

Diameter would be 14 cm, but radius is half of that.

Last verified on 07-06-2026

Explanation

If a real root of f(x) = 0 lies in the interval, then the graph of f(x) must cross the x-axis between a and b.[a][b]

To cross the x-axis:

At one end the function value will be positive, f(a) > 0

At the other end the function value will be negative, f(b) < 0

When signs are opposite, their product is negative.

So f(a) × f(b) < 0

Last verified on 05-06-2026

Explanation

Matrix rows are dependent ⇒ Rank = 2

Determinant of this matrix = 0

So, R − D = 2 − 0 = 2

Last verified on 05-06-2026