In how many ways can the letter of word number taken two at a time

15

Step-by-step explanation:

There are 6 letters in the word number

This is 6 choose 2

This is a combination

The formula is 6! / ( 2! * (6-2)! )

                           6! / 2! 4!

                           (6*5*4*3*2*1) / ( 2*1 *  4*3*2*1)

Canceling like factors

                             (6*5) / ( 2*1)

                              30/2

                                 15

There are 15 possible ways to have 6 choose 2

b. an equilateral triangle inscribed in a circle

step-by-step explanation:

we are given the figure of two circles having a triangle inside.

now, we know that,

"when a figure is lying inside an another figure, then the outside figure is known as circumscribed figure and the figure lying inside is referred to as the inscribed figure".

as we see that, the circles are containing the triangle completely.

thus, the circles are the circumscribed figures and the triangle is the inscribed figure.

hence, we get, 'an equilateral triangle is inscribed in a circle'.