Answer:
a. 4r² b. 2r c. 6 cm
Step-by-step explanation:
The surface area A of the cube is A = 24r². We know that the surface area, A of a cube also equals A = 6L² where L is the length of its side.
Now, equating both expressions, 6L² = 24r²
dividing both sides by 6, we have
6L²/6 = 24r²/6
L² = 4r². Since the area of one face is L², the polynomial that determines the area of one face is A' = 4r².
b. Since L² = 4r² the rea of one face of the cube, taking square roots of both sides, we have
√L² = √4r²
L = 2r
So, the polynomial that represents the length of an edge of the cube is L = 2r
c. The length of an edge of the cube is L = 2r. When r = 3 cm.
L = 2r = 2 × 3 cm = 6 cm
So, the length of an edge of the cube is 6 cm.
A 57.6 B. 100.8 c.78.2 I’m not sure
Answer:
The answer would be -5/12
We can solve this problem in three steps.
<u>1) find the area of the square</u>
![a=lw\\\\a=(7.5)(6)\\\\a=45ft^{2}](https://tex.z-dn.net/?f=a%3Dlw%5C%5C%5C%5Ca%3D%287.5%29%286%29%5C%5C%5C%5Ca%3D45ft%5E%7B2%7D)
<u>2) find the area of the triangle</u>
![a=\frac{1}{2}bh\\\\a=\frac{1}{2} (6)(4)\\\\a=12ft^{2}](https://tex.z-dn.net/?f=a%3D%5Cfrac%7B1%7D%7B2%7Dbh%5C%5C%5C%5Ca%3D%5Cfrac%7B1%7D%7B2%7D%20%286%29%284%29%5C%5C%5C%5Ca%3D12ft%5E%7B2%7D)
<u>3) add the areas together</u>
![a=45+12](https://tex.z-dn.net/?f=a%3D45%2B12)
<em>a = 57 ft²</em>