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3 years ago

Mrs. Palmer asks her students to find the area of the tops of their desks.

Mathematics

1 answer:

xxTIMURxx [149]3 years ago

7 0

Answer:

12 square feet

Step-by-step explanation:

The shape of the top of the desk is a trapezoid.

A = (b1 + b2)h/2

A = (5 ft + 3 ft)(3 ft)/2

A = (8 ft)(3 ft)/2

A = 24 ft^2/2

A = 12 ft^2

Answer: 12 square feet

You might be interested in

First five common multiples of 7and 20

gulaghasi [49]

The first 5 Multiples of 7 are 35, 70, 105, 140, 175
The first 5 Multiples of 20 are: 20, 40, 60, 80, 100

4 0

3 years ago

A national study, that revealed a normal distribution, revealed that the average time a student spends studying statistics on a

Neporo4naja [7]

Answer:

Null hypothesis = H0 : μ = 60

Alternative hypothesis = H1 : μ < 60

Step-by-step explanation:

From the question given :

μ = 60 minutes

xbar = 44.27 minutes

s = 20.4 minutes

The alternative hypothesis is the claim ; which is to hypothesize that the average studying time is 44.27 (which is less than the population average studying time)

The null hypothesis is the initial truth and it is the opposite of the alternative hypothesis.

The hypothesis are :

H0 : μ = 60

H1 : μ < 60

5 0

2 years ago

1.) Find the length of the arc of the graph x^4 = y^6 from x = 1 to x = 8.

xxTIMURxx [149]

First, rewrite the equation so that y is a function of x :

$x^4 = y^6 \implies \left(x^4\right)^{1/6} = \left(y^6\right)^{1/6} \implies x^{4/6} = y^{6/6} \implies y = x^{2/3}$

(If you were to plot the actual curve, you would have both $y=x^{2/3}$ and $y=-x^{2/3}$ , but one curve is a reflection of the other, so the arc length for 1 ≤ x ≤ 8 would be the same on both curves. It doesn't matter which "half-curve" you choose to work with.)

The arc length is then given by the definite integral,

$\displaystyle \int_1^8 \sqrt{1 + \left(\frac{\mathrm dy}{\mathrm dx}\right)^2}\,\mathrm dx$

We have

$y = x^{2/3} \implies \dfrac{\mathrm dy}{\mathrm dx} = \dfrac23x^{-1/3} \implies \left(\dfrac{\mathrm dy}{\mathrm dx}\right)^2 = \dfrac49x^{-2/3}$

Then in the integral,

$\displaystyle \int_1^8 \sqrt{1 + \frac49x^{-2/3}}\,\mathrm dx = \int_1^8 \sqrt{\frac49x^{-2/3}}\sqrt{\frac94x^{2/3}+1}\,\mathrm dx = \int_1^8 \frac23x^{-1/3} \sqrt{\frac94x^{2/3}+1}\,\mathrm dx$

Substitute

$u = \dfrac94x^{2/3}+1 \text{ and } \mathrm du = \dfrac{18}{12}x^{-1/3}\,\mathrm dx = \dfrac32x^{-1/3}\,\mathrm dx$

This transforms the integral to

$\displaystyle \frac49 \int_{13/4}^{10} \sqrt{u}\,\mathrm du$

and computing it is trivial:

$\displaystyle \frac49 \int_{13/4}^{10} u^{1/2} \,\mathrm du = \frac49\cdot\frac23 u^{3/2}\bigg|_{13/4}^{10} = \frac8{27} \left(10^{3/2} - \left(\frac{13}4\right)^{3/2}\right)$

We can simplify this further to

$\displaystyle \frac8{27} \left(10\sqrt{10} - \frac{13\sqrt{13}}8\right) = \boxed{\frac{80\sqrt{10}-13\sqrt{13}}{27}}$

7 0

3 years ago

Sally can paint a room in 8 hours while it takes steve 7 hours to paint the same room. how long would it take them to paint the

77julia77 [94]

Rate for Sally is 1 room per 8hrs
rate for Steve is 1 room per 7hrs

combined rate:
1/8 + 1/7 = 1/T
7/56 + 8/56 = 1/T
15/56 = 1/T
56/15 = T
3 11/15 = 3 hrs 44 min

3 0

2 years ago

Which expression shows a way to find 20% of 950? Please help, I will rate all stars and a thanks if I can. (On i-Ready)

dexar [7]

Answer:

1/5 . 950

This is cause 20% =20/100 and when reduced it is 1/5

5 0

3 years ago