Strange result when using math.tan

[steve-tea]

Hello,

I am playing about with the trig functions and decided to have a go at using "tan" to calculate the height of a building.

The following values are known:

• "angleOfTopOfBuilding": This is the angle of the top of the building from the viewer's perspective.
• "metresFromBuildingAtGroundLevel": This is the distance of the viewer (in metres) from the building
• The viewer is standing at ground level (0 metres)
• angleOfTopOfBuilding = 38.25
• metresFromBuildingAtGroundLevel = 168
• On a handheld calculator the tan of 38.25 is 0.78833643458...
• On a calculator, 168 x 0.788 = 132.384

However, the following program is giving a tan of 0.61432789273532 and a height of 103.20708597953.

Why is there a ≈30 metres difference?

-- title:   tangent
-- author:  steve-tea
-- version: 0.1
-- script:  lua

-- Known variables
angleOfTopOfBuilding = 38.25
metresFromBuildingAtGroundLevel = 168

-- Unknown, must be calculated
heightOfBuilding = 0


function TIC()
	cls(13)
	
	print("tan of 38.25: "..math.tan(angleOfTopOfBuilding),0,8)
        print("Building height: "..math.tan(angleOfTopOfBuilding) * 168,0,16)
end

[steve-tea]

Moving to discord