©G Dear 2009 – Not to be sold/Free to use Mathematics General Preliminary Right Triangles Elevation and Depression. Stage 6 Press Ctrl-A ©G Dear 2009 – Not to be sold/Free to use

Elevation & Depression (1/5) Up Elevation θ θ Depression Down

Angle of Elevation (2/5) A boat is 100 m from a lighthouse. The height og the Lighthouse is 6 m. What is the lighthouse’s angle of elevation? 6 100 tan θo = θo = tan-1 (6 ÷ 100) θo = 3.4336o 6m θo = 3.4o m θo 100m

Angle of Depression (3/5) An aero plane is 1 km from a runway. It is at a height of 300 m. What is the planes angle of depression? 1,000m θO 300 1000 Tan θo = 300 m θo = tan-1 (0.3) θo = 16.6992442o θo = 17o

Angle of Elevation (4/5) A boat is 100m from a lighthouse. It has an angle of elevation of 30o. What is the height of the lighthouse? (h) h 100 tan 30o = h = 100 x Tan 30o h = 57.735 026 919 h h = 57.7 m 30o 100m

Angle of Depression (5/5) An aero plane is 3 km from a runway. The angle of depression is 15o. What is the altitude of the plane? 3 km 15O a 3 tan 15o = a a = 3 x Tan 15o a = 0.803 84 km a = 804 m