Complex Applications with Multiple Angles
Rivers, platforms, and lighthouses offer interesting trigonometry challenges! In problem 15, Mr. Smith stands on a 36-foot cliff and sees two river banks at different angles of depression (53° and 37°). By calculating the distance to each bank and finding the difference, we determine the river is 21 feet wide.
Problem 16 involves two people at different positions. Jennie stands on a platform 15√3 meters high and sees the base of another platform at a 30° angle of depression. Meanwhile, Mark stands on the ground where Jennie sees him at a 60° angle of depression. By calculating both distances from the platform and finding their difference, we determine they're 30 meters apart.
Lighthouses were historically crucial for navigation, and problem 17 shows why! From a 75-meter lighthouse, an observer spots two ships at angles of depression of 30° and 45°. When both ships are in the same line from the lighthouse, we can calculate their horizontal distances and find the distance between them is 52.5 meters.
Real-world Connection: These trigonometric calculations are essential in navigation, construction, astronomy, and engineering. Modern GPS systems use similar principles to determine locations!
Each of these problems follows a pattern: identify what you know, determine the appropriate trigonometric ratio (usually sine, cosine, or tangent), set up an equation, and solve for the unknown value.