Algebra<br> Help me with this question

Suppose you are asked to find the area of a rectangle that is 2.1-cm wide by 5.6-cm long. Your calculator answer would be 11.76

Vladimir79 [104]

Answer:

The area of the rectangle is 12 cm² ⇒ in 2 significant figures

Step-by-step explanation:

* Lets talk about the significant figures

- All non-zero digits are significant

# 73 has two significant figures

- Zeroes between non-zeros digits are significant

# 105.203 has six significant figures

- Leading zeros are never significant

# 0.00234 has three significant figures

- In a number with a decimal point, zeros to the right of the last

non-zero digit are significant

# 19.00 has four significant figures

- Lets make a number and then approximate it to different significant

∵ 12.7360 has 6 significant figures

∴ 12.736 ⇒ approximated to 5 significant figures

∴ 12.74 ⇒ approximated to 4 significant figures

∴ 12.7 ⇒ approximated to 3 significant figures

∴ 13 ⇒ approximated to 2 significant figures

∴ 10 ⇒ approximated to 1 significant figure

- Another number with decimal point

∵ 0.0546700 has 6 significant figures

∴ 0.054670 ⇒ approximated to 5 significant figures

∴ 0.05467 ⇒ approximated to 4 significant figures

∴ 0.0547 ⇒ approximated to 3 significant figures

∴ 0.055 ⇒ approximated to 2 significant figures

∴ 0.05 ⇒ approximated to 1 significant figures

* Lets solve the problem

∵ The width of the rectangle is 2.1 cm

∵ The length of the rectangle is 5.6 cm

- Area of the rectangle = length × width

∴ Area of the rectangle = 2.1 × 5.6 = 11.76 cm²

- Approximate it to two significant figures

∴ Area of the rectangle = 12 ⇒ to the nearest 2 significant figures

* The area of the rectangle is 12 cm² ⇒ in 2 significant figures

3 0

3 years ago

Q7: Determine the graph of the polar equation r = 12/6+4n cos theta.

iVinArrow [24]

Answer:

Choice B

Step-by-step explanation:

The first step is to write the polar equation of the conic section in standard form by dividing the numerator and denominator by 6;

$r=\frac{2}{1+\frac{2}{3}cos theta }$

The eccentricity of this conic section is thus 2/3, the coefficient of cos theta. Clearly, the eccentricity is between o and 1 implying that this conic section represents an Ellipse.

Lastly, the ellipse will open towards the left since we have positive cos theta in the denominator. The only graph that meets the conditions is graph B.

3 0

3 years ago

A normally distributed population has mean 57,800 and standard deviation 750. Find the probability that a single randomly select

Stels [109]

Answer:

(a) Probability that a single randomly selected element X of the population is between 57,000 and 58,000 = 0.46411

(b) Probability that the mean of a sample of size 100 drawn from this population is between 57,000 and 58,000 = 0.99621

Step-by-step explanation:

We are given that a normally distributed population has mean 57,800 and standard deviation 75, i.e.; $\mu$ = 57,800 and $\sigma$ = 750.

Let X = randomly selected element of the population

The z probability is given by;

Z = $\frac{X-\mu}{\sigma}$ ~ N(0,1)

(a) So, P(57,000 <= X <= 58,000) = P(X <= 58,000) - P(X < 57,000)

P(X <= 58,000) = P( $\frac{X-\mu}{\sigma}$ <= $\frac{58000-57800}{750}$ ) = P(Z <= 0.27) = 0.60642

P(X < 57000) = P( $\frac{X-\mu}{\sigma}$ < $\frac{57000-57800}{750}$ ) = P(Z < -1.07) = 1 - P(Z <= 1.07)

= 1 - 0.85769 = 0.14231

Therefore, P(31 < X < 40) = 0.60642 - 0.14231 = 0.46411 .

(b) Now, we are given sample of size, n = 100

So, Mean of X, X bar = 57,800 same as before

But standard deviation of X, s = $\frac{\sigma}{\sqrt{n} }$ = $\frac{750}{\sqrt{100} }$ = 75

The z probability is given by;

Z = $\frac{Xbar-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

Now, probability that the mean of a sample of size 100 drawn from this population is between 57,000 and 58,000 = P(57,000 < X bar < 58,000)

P(57,000 <= X bar <= 58,000) = P(X bar <= 58,000) - P(X bar < 57,000)

P(X bar <= 58,000) = P( $\frac{Xbar-\mu}{\frac{\sigma}{\sqrt{n} } }$ <= $\frac{58000-57800}{\frac{750}{\sqrt{100} } }$ ) = P(Z <= 2.67) = 0.99621

P(X < 57000) = P( $\frac{Xbar-\mu}{\frac{\sigma}{\sqrt{n} } }$ < $\frac{57000-57800}{\frac{750}{\sqrt{100} } }$ ) = P(Z < -10.67) = P(Z > 10.67)

This probability is that much small that it is very close to 0

Therefore, P(57,000 < X bar < 58,000) = 0.99621 - 0 = 0.99621 .

7 0

3 years ago

Luanne made a photocopy of a drawing of a rectangle. The original drawing was 4.5 inches wide and 6 inches long. The copy was 6.

san4es73 [151]

The scale factor is:
$6,75/4,5 = 9/6 = 1,5$

So you divide the corresponding lengths and the ratio you get is the scale factor. Hope it helps!

8 0

3 years ago

Graph x > -3x>−3x, is greater than, minus, 3.

antiseptic1488 [7]

It just is :). Ok ok

4 0

3 years ago

Algebra Help me with this question