All categories

2 years ago

Find the surface area.

Mathematics

1 answer:

denpristay [2]2 years ago

5 0

Step-by-step explanation:

a rectangular prism (like this brick) has the same basic structure as a cube (like a die) : it has 6 sides.

while a die has 6 equal sides, a rectangular prism has 3 pairs of equal sides :

top and bottom

left and right

front and back

all we have to do is calculate the areas of the 6 rectangles and add them up. that's it.

your remember, the area of a rectangle is

length × width

in our case we have

top and bottom : 2.5×11.5 × 2 = 28.75×2 = 57.5 in²

left and right : 2.5×5 × 2 = 12.5×2 = 25 in²

front and back : 11.5×5 × 2 = 57.5×2 = 115 in²

so, the total surface area of the whole block is

57.5 + 25 + 115 = 197.5 in²

You might be interested in

Erin writes the set of ordered pairs below. The set represents a function.

tino4ka555 [31]

Point A shows that she is incorrect.
With functions, you can perform the "straight line test through each point. If the line goes through both points, you know it's not a function.
If we plotted point A, it'd fail the straight line test because the given point (-6, 7) already has -6 as an x value.
Hope this helps!

7 0

3 years ago

Parabolas in geometry. i need help please

natali 33 [55]

Answer:

OPtion B

Step by step explanation:

Lets plug in a random value for x.

Lets say 5 is x

-8(-5-5)=(y+1)^2

5-5 = 0

-8(0) = 0

0 = (y+1)^2

Square root of both sides

0 = y+1

subtract one from both sides

-1 = y

that means the x is 5 and the y is -1. Option B illustrates exactly that!

7 0

3 years ago

PLEASE HELP URGENTLY! ASAP RIGHT ANSWERS WILL BE MARKED BRAINLIEST!!!

WINSTONCH [101]

Answer:

Step-by-step explanation:

the formula for the circumference of a circle is 2rπ

the formula for the area of a circle is (r^2)π

the formula for the diameter of a circle is 2r

π=3.14

---------------------------------------------------------------

1. diameter =2r. since diameter=24, r=12

2. circumference=2rπ. since circumference = 314. 314=2rπ r=49.9746

3. circumference=2rπ area=(r^2)π

since r=7, circumference=14π=43.98229 since r=7, area is 49π=153.9380

4. Since the diameter is 20 the radius is 10. so just insert it into the formulas as before: circumference=20π=62.8318 and area=100π=314.15926

5. the formula for the diameter is 2r=d 2(18)=d, 36=d

6. 2rπ=circumference = 2(5)π=10π=31.415926

Hope that helps :)

8 0

3 years ago

Select the correct answer.

jenyasd209 [6]

Answer:

I think it is B it is my guss

4 0

3 years ago

Sin4x.sin5x+sin4x.sin3x-sin2x.sinx=0

andreev551 [17]

Recall the angle sum identity for cosine:

cos(x + y) = cos(x) cos(y) - sin(x) sin(y)

cos(x - y) = cos(x) cos(y) + sin(x) sin(y)

==> sin(x) sin(y) = 1/2 (cos(x - y) - cos(x + y))

Then rewrite the equation as

sin(4x) sin(5x) + sin(4x) sin(3x) - sin(2x) sin(x) = 0

1/2 (cos(-x) - cos(9x)) + 1/2 (cos(x) - cos(7x)) - 1/2 (cos(x) - cos(3x)) = 0

1/2 (cos(9x) - cos(x)) + 1/2 (cos(7x) - cos(3x)) = 0

sin(5x) sin(-4x) + sin(5x) sin(-2x) = 0

-sin(5x) (sin(4x) + sin(2x)) = 0

sin(5x) (sin(4x) + sin(2x)) = 0

Recall the double angle identity for sine:

sin(2x) = 2 sin(x) cos(x)

Rewrite the equation again as

sin(5x) (2 sin(2x) cos(2x) + sin(2x)) = 0

sin(5x) sin(2x) (2 cos(2x) + 1) = 0

sin(5x) = 0 or sin(2x) = 0 or 2 cos(2x) + 1 = 0

sin(5x) = 0 or sin(2x) = 0 or cos(2x) = -1/2

sin(5x) = 0 ==> 5x = arcsin(0) + 2nπ or 5x = arcsin(0) + π + 2nπ

… … … … … ==> 5x = 2nπ or 5x = (2n + 1)π

… … … … … ==> x = 2nπ/5 or x = (2n + 1)π/5

sin(2x) = 0 ==> 2x = arcsin(0) + 2nπ or 2x = arcsin(0) + π + 2nπ

… … … … … ==> 2x = 2nπ or 2x = (2n + 1)π

… … … … … ==> x = nπ or x = (2n + 1)π/2

cos(2x) = -1/2 ==> 2x = arccos(-1/2) + 2nπ or 2x = -arccos(-1/2) + 2nπ

… … … … … … ==> 2x = 2π/3 + 2nπ or 2x = -2π/3 + 2nπ

… … … … … … ==> x = π/3 + nπ or x = -π/3 + nπ

(where n is any integer)

5 0

3 years ago