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3 years ago

A rectangular prism is 3 units high 2 units wide and 5 units long what is its surface area in square units

Mathematics

1 answer:

Luba_88 [7]3 years ago

6 0

Answer:

62 square units

Step-by-step explanation:

The area of a rectangular prism is the sum of the areas of its six faces. Opposite faces have the same area, so it is the sum of 3 pairs of faces. The area of one face of each pair is the product of the dimensions of that face. Those three areas are ...

• L·W

• W·H

• H·L

so the total surface area is ...

A = 2(LW +WH +HL)

For hand calculation, this can be simplified a bit to ...

A = 2(LW +H(L+W)) . . . . . requires one less multiplication

For your prism, the area is ...

A = 2(5·2 + 3(5+2)) = 2(10 +21) = 62 . . . square units

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Will Jennifer owe money or get a refund? How much?

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Answer:

owe money 24,000

Step-by-step explanation:

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3 years ago

Semielliptical Arch Bridge An arch for a bridge over a highway is in the form of half an ellipse. The top of the arch is 20 feet

photoshop1234 [79]

Answer:

the span of the bridge is 73.7 feet

Step-by-step explanation:

The equation of an ellipse with a vertical major axis(i.e major axis parallel to y axis) is given by:

$\frac{(x-h)^{2} }{b^{2} } + \frac{(y-k)^{2} }{a^{2} }= 1$ a>b

where (h,k) are the coordinates of the center of the ellipse, a is the length of the major axis and b is the length of the minor axis

For this problem, the center of the ellipse (h,k) = (0,0)

Therefore:

$\frac{(x)^{2} }{b^{2} } + \frac{(y)^{2} }{a^{2} }= 1$

The top of the arch is 20 feet above the ground level (the major axis), therefore a=20

length of the major axis = 2a= 2*20 = 40

$\frac{x^{2} }{b^{2} } + \frac{y^{2} }{20^{2} }= 1\\\frac{x^{2} }{b^{2} } + \frac{y^{2} }{400 }= 1$

The coordinates of the ellipse (x,y) = (28,13)

$\frac{28^{2} }{b^{2} } + \frac{13^{2} }{400 }= 1$

$\frac{28^{2} }{b^{2} } + 0.4225= 1$

$\frac{784 }{b^{2} } = 0.5775$

b² ≅ 1358

b≅36.85

Length of minor axis (2b) = 73.7 feet.

the span of the bridge is 73.7 feet

7 0

3 years ago

Let $P$ and $Q$ be constants. The graphs of the lines $x + 5y = 7$ and $15x + Py = Q$ are perpendicular and intersect at the poi

Marta_Voda [28]

Answer:

(-3, -129)

Step-by-step explanation:

Given

Two lines:

$x + 5y = 7$

$15x + Py = Q$

are perpendicular to each other and intersect at point (-8,3).

To find: (P, Q)

Solution:

The two lines intersect at (-8,3).

It means, the equation of line will be satisfied when we put value of x = -8 and y = 3

Putting in the second equation, we will get an equation in P and Q:

$15\times (-8) + P \times 3 = Q\\\Rightarrow 3P = Q +120 ..... (1)$

Given that two lines are perpendicular.

It means the product of their slopes will be equal to -1.

i.e. $m_1\times m_2=-1$

Slope of a line of the form $ax+by+c=0$ is given as:

$m=-\dfrac{a}{b}$

So, slopes of given lines are:

$m_1=-\dfrac{1}{5}\\m_2=-\dfrac{15}{P}$

Using the condition:

$-\dfrac{1}{5}\times \dfrac{-15}{P}=-1\\\Rightarrow P = -3$

Putting the value of P in equation (1):

$\Rightarrow 3\times (-3) = Q +120 \\\Rightarrow Q = -9-120 = -129$

So, answer is (-3, -129)

7 0

3 years ago

I NEED HELP PLEASEEEEEE

dybincka [34]

Answer:

A. The function is always decreasing

Step-by-step explanation:

we read a graph from left to right, so we can always compare the increase/decrease of a function by seeing how an x value compares with an x value to the left

(I am aware that this paragraph is really confusing)

we can see that as x increases, from -∞ to 0,

y decreases in correspondence

and that as x increases, from 0 to ∞,

y decreases in correspondence also

So, even though the graph doesn't quite look like it, when x < 0; the function decreases, when x > 0; function decreases--so the function is always decreasing

hope this helps!! have a lovely day :)

5 0

2 years ago

If 2x+5= 12 for some value of x, then what does 6x+20 equal???

ANEK [815]

1. Solve for x in 2x + 5 = 12
2x + 5 = 12 Subtract 5 from both sides.
2x = 7 Divide 2 from both sides.
x = 3.5

2. Substitute 3.5 in for x in 6x + 20
6(3.5) + 20
21 + 20
41

Your answer is 41.

6 0

3 years ago

Read 2 more answers