Soru

Zorluk: OrtaVolume and Surface Area of Solids

A right circular cone has a volume of 24 cubic centimeters24\text{ cubic centimeters}. A second right circular cone has a base radius that is 33 times the base radius of the first cone, and a height that is half the height of the first cone. What is the volume, in cubic centimeters, of the second cone?

  1. A
    36
  2. 108Cevap
  3. C
    216
  4. D
    324

Cevap

108
The volume of a cone is proportional to the square of its radius and directly proportional to its height. Tripling the radius increases the volume by a factor of 32=93^2 = 9. Halving the height reduces the volume by a factor of 12\frac{1}{2}. Combining these changes scales the original volume by 9×12=4.59 \times \frac{1}{2} = 4.5. Multiplying the original volume of 2424 by 4.54.5 gives the correct volume of 108108.

Adım Adım Çözüm

1
Write down the formula for the volume of a right circular cone.
V=13πr2hV = \frac{1}{3}\pi r^2 h
This establishes the relationship between volume, radius, and height.
2
Express the volume of the second cone (V2V_2) in terms of the dimensions of the first cone (rr and hh).
V2=13π(3r)2(12h)V_2 = \frac{1}{3}\pi (3r)^2 \left(\frac{1}{2}h\right)
The radius of the second cone is 3r3r and the height is 12h\frac{1}{2}h.
3
Simplify the expression for the second cone's volume to find the scale factor relative to the first cone.
V2=13π(9r2)(12h)=92(13πr2h)=4.5V1V_2 = \frac{1}{3}\pi (9r^2) \left(\frac{1}{2}h\right) = \frac{9}{2} \left(\frac{1}{3}\pi r^2 h\right) = 4.5 V_1
Squaring the radius multiplier of 3 gives a factor of 9, and the height multiplier of 0.5 gives a factor of 0.5, resulting in a combined scaling factor of 4.5.
4
Calculate the final volume using the volume of the first cone (V1=24V_1 = 24).
V2=4.5×24=108V_2 = 4.5 \times 24 = 108
Multiplying the original volume of 24 cm324\text{ cm}^3 by the overall scale factor of 4.54.5 yields the new volume.

Anahtar Kavram

Dimensional scaling of three-dimensional solids
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