Difference between revisions of "1992 AIME Problems/Problem 7"
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== Solution == | == Solution == | ||
| − | {{ | + | Since the area <math>BCD=80=\frac{1}{2}\cdot10\cdot16</math>, the perpendicular from D to BC has length 16. |
| + | |||
| + | The perpendicular from D to ABC is <math>16 \cdot sin 30^\circ=8</math>. Therefore, volume=<math>\frac{8\cdot120}{3}=320</math>. | ||
== See also == | == See also == | ||
Revision as of 12:18, 28 December 2007
Problem
Faces 
and 
of tetrahedron 
meet at an angle of 
. The area of face is 
, the area of face is 
, and 
. Find the volume of the tetrahedron.
Solution
Since the area 
, the perpendicular from D to BC has length 16.
The perpendicular from D to ABC is 
. Therefore, volume=
.
See also
| 1992 AIME (Problems • Answer Key • Resources) | ||
| Preceded by Problem 6 |
Followed by Problem 8 | |
| 1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 | ||
| All AIME Problems and Solutions | ||
