7.) Area of a square pyramid is given by A = s^2 + 2sl; where s is the side length of the base and l is the slant height.
Area of given pyramid = 4^2 + (2 x 4 x 7) = 16 + 56 = 72 ft^2

8.) Area of the given pyramid is the area of the hexagonal base plus the area of the six slant triangles.
Area of hexagonal base = (3sqrt(3))/2 x 10^2 = 150 x 1.732 = 259.8
Area of the 6 traingles = 6(1/2 x 10 x 13) = 6 x 65 = 390
Total surface area of the pyramid = 259.8 + 390 = 649.8 ≈ 650 m^2

9.) Using pythagoras rule, the slant height is sqrt(6^2 + 3.5^2) = sqrt(36 + 12.25) = sqrt(48.25) = 6.9 mm

10.) The surface area of a cone is given by πr^2 + πrl
Area = π x 6^2 + π x 6 x 20 = 36π + 120π = 490.1 cm^2

11.) l = sqrt(r^2 + h^2) = sqrt(11^2 + 16^2) = sqrt(121 + 256) = sqrt(377) = 19m

6 0

3 years ago

Harold uses a cone shaped feeder, with a diameter of 7.5 centimeters and a height of 3.5 centimeters, to feed his tropical fish.

Ilia_Sergeevich [38]

To find the volume of a cone you use the formula "1/3 x 3.14 x r^2 x h". Plug the formula into the problem. 1/3 x 3.14 x 3.75^2 x 3.5 =51.51. Rounded to the nearest tenth is 51.5. Hope this helps!

4 0

3 years ago

Read 2 more answers

An account grows at an annual interest rate of r⁡ ⁣, so it grows by a factor of x=1+r⁡ ⁣⁣ ⁡ each year. The function A(x)=800x

Paladinen [302]

Given:

Annual interest rate = r⁡%

Growth factor : x = 1 + r⁡

The below function gives the amount in the account after 4 years when the growth factor is x⁡ ⁣⁣.

$A(x)=800x^4+350x^3+500x^2+600x$

To find:

The total amount in the account if the interest rate for the account is 3% each year and initial amount.

Solution:

Rate of interest = 3% = 0.03

Growth factor : x = 1 + ⁡0.03 = 1.03

We have,

$A(x)=800x^4+350x^3+500x^2+600x$

Substitute x=1.03 in the given function, to find the total amount in the account if the interest rate for the account is 3% each year.

$A(1.03)=800(1.03)^4+350(1.03)^3+500(1.03)^2+600(1.03)$

$A(1.03)=800(1.12550881)+350(1.092727)+500(1.0609
)+618$

$A(1.03)=900.407048+382.45445+530.45+618$

$A(1.03)=2431.311498
$

$A(1.03)\approx 2431.31
$

Therefore, the total amount in the account is 2431.31 if the interest rate for the account is 3% each year.

For initial amount the rate of interest is 0.

Growth factor : x = 1 + ⁡0 = 1

Substitute x=0 in the given function to find the initial amount.

$A(1)=800(1)^4+350(1)^3+500(1)^2+600(1)$

$A(1)=800+350+500+600$

$A(1)=2250$

Therefore, 2250 was put into the account at the beginning.

3 0

3 years ago

Assume that a set of test scores is normally distributed with a mean of 70 and a standard deviation of 10. In what percentile is

vlabodo [156]

Given:
μ = 70, the mean
σ = 10, the standard deviation

The random variable is x = 65.
Calculate the z-score.
z = (x - μ)/σ = (65 -70)/10 = - 0.5

From standard ables, obtain
P(x<5) = 0.3085 ≈ 30%
The score of 65 is in the 30th percentile.

Answer: 30th

3 0

3 years ago