document.write( "Question 628648: A person is watching a boat from the top of a lighthouse. The boat is approaching the lighthouse directly. When first noticed the angle of depression to the boat is 17°31'. When the boat stops, the angle of depression is 46°41'. The lighthouse is 200 feet tall. How far did the boat travel from when it was first noticed until it stopped? Round your answer to the hundredths place. \n" ); document.write( "
Algebra.Com's Answer #395791 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! A person is watching a boat from the top of a lighthouse. \n" ); document.write( "The boat is approaching the lighthouse directly. \n" ); document.write( "When first noticed the angle of depression to the boat is 17°31'. \n" ); document.write( "When the boat stops, the angle of depression is 46°41'. \n" ); document.write( "The lighthouse is 200 feet tall. \n" ); document.write( "How far did the boat travel from when it was first noticed until it stopped? \n" ); document.write( " Round your answer to the hundredths place. \n" ); document.write( ": \n" ); document.write( "Change 17 degrees 31 minutes to 17 + 31/60 = 17.5167 degrees \n" ); document.write( "Change 46 degrees 41 minutes to 46.6833 degrees \n" ); document.write( ": \n" ); document.write( "We can solve this using two right triangles \n" ); document.write( "90 - 17.5167 = 72.4833 \n" ); document.write( "Side opposite will be distance (D) from the lighthouse to the boat when noticed \n" ); document.write( "Side adjacent: the lighthouse; 200 ft \n" ); document.write( "tan(72.4833) = \n" ); document.write( "D = 3.16837 * 200 \n" ); document.write( "D = 633.675 ft, lighthouse to boat when noticed \n" ); document.write( ": \n" ); document.write( "The 2nd right triangle: \n" ); document.write( "90 - 46.6833 = 43.3167 \n" ); document.write( "side opposite will be distance (d) from lighthouse to boat when it stopped \n" ); document.write( "tan(43.3167) = \n" ); document.write( "d = .9429 * 200 \n" ); document.write( "d = 188.580 ft, lighthouse to boat it stopped \n" ); document.write( ": \n" ); document.write( "Boat traveled: 633.675 - 188.580 = 445.09 ft \n" ); document.write( " |