9: R3: A lighthouse is east of a sailboat. The sailboat's dock is 30km south of the lighthouse. The captain measures the angle between the lighthouse and the dock and finds it to be 40 degrees. How far is the sailboat from the dock? Round to the nearest whole km.
Q. 9: R3: A lighthouse is east of a sailboat. The sailboat's dock is 30km south of the lighthouse. The captain measures the angle between the lighthouse and the dock and finds it to be 40 degrees. How far is the sailboat from the dock? Round to the nearest whole km.
Identify Triangle Formed: Identify the triangle formed by the lighthouse, dock, and sailboat. The dock is 30km south of the lighthouse, forming a right triangle with the sailboat.
Use Tangent Function: Use the angle given, 40 degrees, to find the distance from the sailboat to the dock using the tangent function. tan(40∘)=adjacentopposite=30 kmdistance from sailboat to dock.
Solve for Distance: Rearrange the equation to solve for the distance from the sailboat to the dock. Distance =30km×tan(40∘). Calculate tan(40∘)≈0.8391. So, Distance ≈30km×0.8391.
Perform Multiplication: Perform the multiplication to find the distance. Distance ≈30km×0.8391≈25.173km.
Round to Nearest km: Round the distance to the nearest whole km. Distance ≈25 km.