Explanation

To convert (10101)₂ to decimal: = 1×2⁴ + 0×2³ + 1×2² + 0×2¹ + 1×2⁰

= 16 + 0 + 4 + 0 + 1

= 21

Explanation

A compass is used for drawing circles and arcs.

It has a pointed end for the center and a pencil or pen for marking the circle.

Explanation

B - A represents the set of elements that are in B but not in A.

The correct notation is: {x | x ∈ B and x ∉ A}

Explanation

For the multiplication of two matrices A (size m x p) and B (size p x n), the resulting matrix AB will have dimensions m x n.

The number of rows of A and the number of columns of B determine the dimensions of the product matrix.

Explanation

The surface area of a sphere depends only on the radius (r) and is given by the formula 4πr².

This formula comes from calculus and represents the total area covering the outer layer of a perfect sphere.