If 2 <br> Please help me Im super confused

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

so

$r=\frac{b}{2}=\frac{4}{2}=2\ cm$ ---> 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:

so

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

---> exact value

assume

$\pi =3.14$

substitute

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

8 0

3 years ago

The spiders and ants in Aunt Mellys attic have a total of 152 legs and 22 heads. Spiders have 8 legs and ants have 6 legs. How m

Scorpion4ik [409]

Answer:

10 spiders and 12 ants

Step-by-step explanation:

You need to create two equations

s = # of spiders

a = # of ants

s + a = 22 heads

since each spider and ant has one head

8s + 6a = 152 legs

since every spider has 8 legs and every ant has 6

s + a = 22 can be turned into s = 22 - a

now use substitution

8(22 - a) + 6a = 152

176 - 8a + 6a = 152

176 - 2a = 152

24 = 2a

a = 12

now that you have the number of ants you can solve for the number of spiders

s + a = 22

s + 12 = 22

s = 10

6 0

1 year ago

Maya is showing her work in simplifying (5.2 − 4.5) − 5.5 + 4.8. Identify any error in her work or reasoning.

Dmitry_Shevchenko [17]

If putting 5.2 and 4.5 in fraction form, her error must have been timing 3 by 3 to 5.2 and 4.5 as a fraction. Meaning that 5.5 and 4.8 is wrong

7 0

2 years ago

A college-entrance exam is designed so that scores are normally distributed with a mean of 500 and a standard deviation of 100.

Crank

Answer: 1.25

Step-by-step explanation:

Given: A college-entrance exam is designed so that scores are normally distributed with a mean $(\mu)$ = 500 and a standard deviation $(\sigma)$ = 100.

A z-score measures how many standard deviations a given measurement deviates from the mean.

Let Y be a random variable that denotes the scores in the exam.

Formula for z-score = $\dfrac{Y-\mu}{\sigma}$

Z-score = $\dfrac{625-500}{100}$

⇒ Z-score = $\dfrac{125}{100}$

⇒Z-score =1.25

Therefore , the required z-score = 1.25

6 0

3 years ago

(3x+14)° measurement in degrees a.20.00° b.40.25° c.42.50° d.74.00°

Marysya12 [62]

Answer:

B

Step-by-step explanation:

4 0

2 years ago

If 2 Please help me Im super confused