+0  
 
0
1923
1
avatar

From a hot air balloon, the angle between a radio antenna straight below and the base of the library downtown is 63°, as shown below. If the distance between the radio antenna and the library is 24 miles, how many miles high is the balloon?

 May 22, 2014

Best Answer 

 #1
avatar+33663 
+5

tan(64°) is given by the distance from radio mast to library, divided by height of balloon (h), or:

tan(64°)=24/h

Rearrange to get h = 24/tan(64°)

$${\mathtt{h}} = {\frac{{\mathtt{24}}}{\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}{\left({\mathtt{64}}^\circ\right)}}} \Rightarrow {\mathtt{h}} = {\mathtt{11.705\: \!582\: \!125\: \!582\: \!365\: \!3}}$$ 

h ≈ 11.7 miles

 Edit:  I should have used 63° not 64° in the above!!  

         Thanks for pointing this out Chris.

$${\mathtt{h}} = {\frac{{\mathtt{24}}}{\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}{\left({\mathtt{63}}^\circ\right)}}} \Rightarrow {\mathtt{h}} = {\mathtt{12.228\: \!610\: \!787\: \!867\: \!229\: \!7}}$$

h ≈ 12.2 miles

 May 22, 2014
 #1
avatar+33663 
+5
Best Answer

tan(64°) is given by the distance from radio mast to library, divided by height of balloon (h), or:

tan(64°)=24/h

Rearrange to get h = 24/tan(64°)

$${\mathtt{h}} = {\frac{{\mathtt{24}}}{\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}{\left({\mathtt{64}}^\circ\right)}}} \Rightarrow {\mathtt{h}} = {\mathtt{11.705\: \!582\: \!125\: \!582\: \!365\: \!3}}$$ 

h ≈ 11.7 miles

 Edit:  I should have used 63° not 64° in the above!!  

         Thanks for pointing this out Chris.

$${\mathtt{h}} = {\frac{{\mathtt{24}}}{\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}{\left({\mathtt{63}}^\circ\right)}}} \Rightarrow {\mathtt{h}} = {\mathtt{12.228\: \!610\: \!787\: \!867\: \!229\: \!7}}$$

h ≈ 12.2 miles

Alan May 22, 2014

2 Online Users