Ask question

Ask question

All categories

3 years ago

5

A rectangle has an area of 18cm2 (squared). The lengths of the sides are whole numbers. How long could the sides of the rectangl

e be?
Give all the examples you can think of

This is mathswatch i need help on it. the deadline for this work is on 27/05/2020

1 answer:

marishachu [46]3 years ago

7 0

Answer:

9 cm, 2 cm

or

6 cm , 3 cm

Step-by-step explanation:

There are two possibilities of the lengths of the sides of rectangle

$18= 9\times 2\\18=6\times 3\\$

You might be interested in

Use the graph to solve the system of linear equations.<br> x+y=5<br> y – 2x = -4

Romashka [77]

Y=-x+5
Y=2x-4
X would be your slope
Y intercepts would be (0, 5) , ( 0,-4)
Formula i used was Y=Mx+B

3 0

3 years ago

Are 4 and 9 relatively prime?

SSSSS [86.1K]

Answer:

nbvStep-by-step explanation:

6 0

3 years ago

Read 2 more answers

Each batch of 48 cookies that Amy makes takes 20 minutes in the oven. If the oven is on for 3 hours and 55 minutes (15 minutes f

Alexxx [7]

3 hours and 55 minutes - 15 minutes would leave 3 hours and 40 minutes. You figure there’s 20 minutes 3 times in an hour so 3x3 is 9 + the extra 2 20 minute periods from the 40 minutes. So 11 batches of cookies, 48x11= 528. Amy made 528 cookies.

5 0

2 years ago

Please help thank you

sergiy2304 [10]

8-3(2)
8-5
=3
the answer should be 3 after plugging in the variables.

3 0

3 years ago

A norman window is constructed by adjoining a semicircle to the top of an ordinary rectangular. Find the dimensions of a norman

Yanka [14]

Answer:

$W\approx 8.72$ and $L\approx 15.57$ .

Step-by-step explanation:

Please find the attachment.

We have been given that a norman window is constructed by adjoining a semicircle to the top of an ordinary rectangular. The total perimeter is 38 feet.

The perimeter of the window will be equal to three sides of rectangle plus half the perimeter of circle. We can represent our given information in an equation as:

$2L+W+\frac{1}{2}(2\pi r)=38$

We can see that diameter of semicircle is W. We know that diameter is twice the radius, so we will get:

$2L+W+\frac{1}{2}(2r\pi)=38$

$2L+W+\frac{\pi}{2}W=38$

Let us find area of window equation as:

$\text{Area}=W\cdot L+\frac{1}{2}(\pi r^2)$

$\text{Area}=W\cdot L+\frac{1}{2}(\pi (\frac{W}{2})^2)$

$\text{Area}=W\cdot L+\frac{\pi}{2}(\frac{W}{2})^2)$

$\text{Area}=W\cdot L+\frac{\pi}{2}(\frac{W^2}{4})$

$\text{Area}=W\cdot L+\frac{\pi}{8}W^2$

Now, we will solve for L is terms W from perimeter equation as:

$L=38-(W+\frac{\pi }{2}W)$

Substitute this value in area equation:

$A=W\cdot (38-W-\frac{\pi }{2}W)+\frac{\pi}{8}W^2$

Since we need the area of window to maximize, so we need to optimize area equation.

$A=W\cdot (38-W-\frac{\pi }{2}W)+\frac{\pi}{8}W^2$

$A=38W-W^2-\frac{\pi }{2}W^2+\frac{\pi}{8}W^2$

Let us find derivative of area equation as:

$A'=38-2W-\frac{2\pi }{2}W+\frac{2\pi}{8}W$

$A'=38-2W-\pi W+\frac{\pi}{4}W$

$A'=38-2W-\frac{4\pi W}{4}+\frac{\pi}{4}W$

$A'=38-2W-\frac{3\pi W}{4}$

To find maxima, we will equate first derivative equal to 0 as:

$38-2W-\frac{3\pi W}{4}=0$

$-2W-\frac{3\pi W}{4}=-38$

$\frac{-8W-3\pi W}{4}=-38$

$\frac{-8W-3\pi W}{4}*4=-38*4$

$-8W-3\pi W=-152$

$8W+3\pi W=152$

$W(8+3\pi)=152$

$W=\frac{152}{8+3\pi}$

$W=8.723210$

$W\approx 8.72$

Upon substituting $W=8.723210$ in equation $L=38-(W+\frac{\pi }{2}W)$ , we will get:

$L=38-(8.723210+\frac{\pi }{2}8.723210)$

$L=38-(8.723210+\frac{8.723210\pi }{2})$

$L=38-(8.723210+\frac{27.40477245}{2})$

$L=38-(8.723210+13.70238622)$

$L=38-(22.42559622)$

$L=15.57440378$

$L\approx 15.57$

Therefore, the dimensions of the window that will maximize the area would be $W\approx 8.72$ and $L\approx 15.57$ .

8 0

3 years ago