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3 years ago

How do you use an exponent to represent a number such as 81?

Mathematics

1 answer:

Mama L [17]3 years ago

8 0

Answer:

9²

Step-by-step explanation:

9 × 9 = 81

Nine to the power of Two

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Semicircles

Studentka2010 [4]

Answer:

The area of the shaded portion of the figure is $9.1\ cm^2$

Step-by-step explanation:

see the attached figure to better understand the problem

we know that

The shaded area is equal to the area of the square less the area not shaded.

There are 4 "not shaded" regions.

step 1

Find the area of square ABCD

The area of square is equal to

$A=b^2$

where

b is the length side of the square

we have

$b=4\ cm$

substitute

$A=4^2=16\ cm^2$

step 2

We can find the area of 2 "not shaded" regions by calculating the area of the square less two semi-circles (one circle):

The area of circle is equal to

$A=\pi r^{2}$

The diameter of the circle is equal to the length side of the square

$r=\frac{b}{2}=\frac{4}{2}=2\ cm$ ---> radius is half the diameter

substitute

$A=\pi (2)^{2}$

$A=4\pi\ cm^2$

Therefore, the area of 2 "not-shaded" regions is:

$A=(16-4\pi) \ cm^2$

and the area of 4 "not-shaded" regions is:

$A=2(16-4\pi)=(32-8\pi)\ cm^2$

step 3

Find the area of the shaded region

Remember that the area of the shaded region is the area of the square less 4 "not shaded" regions:

$A=16-(32-8\pi)=(8\pi-16)\ cm^2$

---> exact value

assume

$\pi =3.14$

substitute

$A=(8(3.14)-16)=9.1\ cm^2$

8 0

3 years ago

PLS HELP

Anika [276]

The chairs in the auditorium illustrates an arithmetic sequence

The recursive rule is: an = an-1 + 8; a1 = 26
The explicit rule is: an = 18 + 8n
There are 74 seats in the 7th row
840 chairs can fit the auditorium

<h3>The recursive rule</h3>

From the question, we have the following sequence:

Seats: 18, 26, 34

Rewrite as:

26 = 18 + 8

34 = 26 + 8

The above means that:

The number of seats on a row is 8 added to the the number of seats on the previous row.

Hence, the recursive rule is:

an = an-1 + 8; a1 = 26

<h3>The explicit rule</h3>

In (a), we have:

a1 = 26 and d = 8

The explicit rule is calculated using:

an = a1 + (n -1) * d

This gives

an = 26 + (n - 1) * 8

Expand

an = 26 - 8 + 8n

Evaluate the difference

an = 18 + 8n

Hence, the explicit rule is:

an = 18 + 8n

<h3>The number of seats in the row 7</h3>

This means that n = 7.

So, we have:

a7 = 18 + 8 * 7 = 74

Hence, there are 74 seats in the 7th row

<h3>The sigma notation</h3>

We have the maximum number of rows to be 12.

So, the sigma notation would be:

$\sum\limits^{12}_{n=1} {18 + 8n}$

The total number of seats is:

Sn = n/2(2a + (n -1) * d)

This gives

S12 = 12/2(2 * 26 + (12 -1) * 8)

S12 = 840

Hence, 840 chairs can fit the auditorium

Read more about arithmetic sequence at:

brainly.com/question/6561461

7 0

2 years ago

In deciding the best medium to tell a story, which step is first?(1 point)

zavuch27 [327]

Answer:

identifying the audience

Step-by-step explanation:

6 0

2 years ago

It takes Mike 18 minutes to finish reading 4 pages of a book. How long does it take for him to finish reading 30 pages

dusya [7]

Answer:

Step-by-step explanation:

5 0

3 years ago

Sam wants to find the best buy on cans of tuna. He reads these four ads in the newspaper.$12.53 for seven cans$5.97 for three ca

grandymaker [24]

In each case divide the price by the number of cans.
The best buy is the lowest price.
$12.53/7 = $1.79
$5.97/3 = $1.99
$7.95/5 = $1.59
$8.34/6 = $1.39

The fourth ad, $8.34 for 6 cans results in the lowest price per can, $1.39.
The fourth ad is the best buy.

8 0

3 years ago