Misha wants to know how much wrapping paper is needed to cover a box with the dimensions shown.
1 answer:
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Answer:
Radius, r, is 3.75
Step-by-step explanation:
From the given diagram,
AB = 9
AC = 6 + r
BC = r
Thus applying the Pythagoras theorem, we have;
=
+
=
+
36 + 12r + = 81 +
collecting like terms,
12r = 81 - 36
12r = 45
r =
= 3.75
r = 3.75
The radius is 3.75.
Formula of the Volume of a hemisphere:
V =
r³
144
= r³
Multiply by 3 to cancel fraction in the right side
144 × 3 = 2 r³
432 = 2r³
Divide by 2 on either sides to isolate r³
= 
r³
2 and 
cancel out
216 = r³
Take cube root to find the radius
![\sqrt[3]{216}](https://tex.z-dn.net/?f=%20%5Csqrt%5B3%5D%7B216%7D%20)
= ![\sqrt[3]{r^3}](https://tex.z-dn.net/?f=%20%5Csqrt%5B3%5D%7Br%5E3%7D%20)
6 = r
Radius is 6 units
The formula of the surface area of a hemisphere is:
S.A = 2r² + r²
=
(6)² + (6)²
=2 × 36 + 36
= 72 + 36
= 108 units² (in terms of )
≈ 339.12 units²
Surface area = 108 units
V =
144
Multiply by 3 to cancel fraction in the right side
144
432
Divide by 2
2
216 = r³
Take cube root to find the radius
6 = r
Radius is 6 units
The formula of the surface area of a hemisphere is:
S.A = 2
=
=2
= 72
= 108
≈ 339.12 units²
Surface area = 108