Question

There are 7 dots on a piece of paper. NO 3 dots are in a straight line. How many line segments are needed to connect each dot to every dot?

Answer 1

The question is an illustration of permutation and combinations.

The number of lines from 7 dots is 21.

Given

$n = 7$ --- number of dots

$r= 2$ ----- 2 points make a line

The number of lines is calculated using the following formula:

$Lines = \frac{n \times (n -1)}{2}$

So, we have:

$Lines = \frac{7 \times (7 -1)}{2}$

Subtract 1 from 7

$Lines = \frac{7 \times 6}{2}$

Divide 6 by 2

$Lines = 7 \times 3$

Multiply 7 and 3

$Lines = 21$

Hence, the number of lines is 21.

Read more about permutation and combinations at:

brainly.com/question/15301090