Can someone help me with this problem

a ladder that is 20 feet long is leaning against the side of a building if the angle formed between the ladder and the ground is

Mademuasel [1]

Answer:

Step-by-step explanation:

Take 20( cosine of 75 degrees)

the answer is 5 ft

8 0

4 years ago

Read 2 more answers

A rectangular box which is open at the top can be made from an12-by-18-inch piece of metal by cutting a square from each corner

algol [13]

Answer:

h=2.35in, l=13.3in and w=7.3in

Step-by-step explanation:

In order to solve this problem, we must start by drawing a diagram that will represent the prolem. (Look at attached picture)

From the diagram we can see that the length ad the width of the box are found by using the following expressions:

L=18-2x

W= 12-2x

H=x

next, we can make use of the volume formula of a rectangular prism, which is the following:

V=WLH

so we can substitute the expressions we got before on the formula:

V=x(12-2x)(18-2x)

and for ease of calculation, we can multiply the terms, so we get:

$V=x(216-24x-36x+4x^{2})$

$V=x(4x^{2}-60x+216)$

$V=4x^{3}-60x^{2}+216x$

So now we can find the derivative of the volume:

$V'=12x^{2}-120x+216$

and set it equal to zero, so we get:

$12x^{2}-120x+216=0$

and now we can solve. We can start by factoring the left side of the equation, so we get:

$12(x^{2}-10x+18)=0$

which yields:

x^{2}-10x+18=0

This one can only be solved by using the quadratic formula:

$x=\frac{-b\pm \sqrt{-b^{2}-4ac}}{2a}$

so we substitute the corresponding values:

$x=\frac{-(-10)\pm \sqrt{-(-10)^{2}-4(1)(18)}}{2(1)}$

which yields:

x=7.65in or x=2.35in

we keep the 2.35in only, because the 7.65in returns an impossible box, since that would make the width a negative width.

So the 2.35in height would give us the greatest box. Now we can use it to find the height, the width and the length of the box.

Height=x=2.35

W=12-2x=12-2*2.35=7.3in

L=18-2x=18-2(2.35)=13.3in

5 0

3 years ago

Line L passes through the points (0, --3) and (6,9).<br> (a) Find the equation of line L.

valentina_108 [34]

Step-by-step explanation:

Given points are :

$(0,\:-3)=(x_1,\:y_1) \:\&\: (6,\:9)=(x_2 ,\:y_2)$

Equation of line in two point form is given as:

$\frac{y -y_1 }{y_1 -y_2 } = \frac{x -x_1 }{x_1 -x_2 } \\ \\ \therefore \frac{y -( - 3)}{ -3 -9 } = \frac{x -0 }{0 -6 } \\ \\ \therefore \frac{y + 3}{ -12} = \frac{x }{ -6 } \\ \\ \therefore \frac{y + 3}{ 2} = \frac{x }{1} \\ \\ \therefore \: y + 3 = 2x \\ \\ \huge \red{ \boxed{\therefore \: 2x - y - 3 = 0}} \\ is \: the \: required \: equation \: of \: line.$

5 0

3 years ago

Find the volume of a pyramid with a square base, where the perimeter of the base is

grigory [225]

Answer:

90.3125 cm³

Step-by-step explanation:

Since the perimeter of the bottom square is 17, you can divide by four to find out what the lenght of each side is.

17/4=4.25 cm

We know the height of pyramid is 15 cm

The formula for the volume of a square pyramid is

V=a²(h/3)

V=a2(h/3)=4.252·15/3=90.3125 cm³

8 0

3 years ago

From a distance of 42 feet from the base of a building, the angle of elevation to the top of the building is 67 degrees. Estimat

Nataliya [291]

A diagram would surely help here. But imagine that you stand at spot A and someone finds that your distance from the base of the building is 42 feet. Call this point B.

Imagine a vertical line from that spot, straight up. Label the top of this line C.

The acute angle at A is 67 degrees. You want to find the height of the building, which would be the length of the "opposite side of triangle ABC."
The length of the "adjacent side of triangle ABC" would be 42 feet.

We don't know the length of the hypotenuse, altho' we could easilyl calculate it using the Pyth. Them.

We choose the tangent function to solve for the height of the building (which is the length of the opposite side.

height
By definition, tangent (67 degrees) = -------------------------------------
42 feet

Find tan 67. Multiply your result by 42 feet. This product is the height of the building.

7 0

4 years ago