Answer:
9r²(r - 8)
Step-by-step explanation:
Step 1: Write expression
9r³ - 72r²
Step 2: Factor out 9
9(r³ - 8r²)
Step 3: Factor out r²
9r²(r - 8)
A pyramid is regular if its base is a regular polygon, that is a polygon with equal sides and angle measures.
(and the lateral edges of the pyramid are also equal to each other)
Thus a regular rectangular pyramid is a regular pyramid with a square base, of side length say
x.
The lateral faces are equilateral triangles of side length
x.
The lateral surface area is 72 cm^2, thus the area of one face is 72/4=36/2=18 cm^2.
now we need to find
x. Consider the picture attached, showing one lateral face of the pyramid.
by the Pythagorean theorem:

thus,

thus:

(cm^2)
but

is exactly the base area, since the base is a square of sidelength =
x cm.
So, the total surface area = base area + lateral area =

cm^2
Answer:

cm^2
Answer:
32 and 4
Step-by-step explanation:
128=2^7
(8xa)xb=128
axb=2^4=16
(8x4)x4=128
Answer:
Decay
since 0.292 is less than 1
% rate of decrease
1 - 0.292 = 0.708
70.8%
Answer:
219,000
Step-by-step explanation:
How many 6 hour periods are in a day?
24 divided by 6 is 4.
150 times 4 equals 600
finally 600 times 365 equals 219,000 planes a year