Centered triangle body

physics = require("physics")
physics.start()
physics.setGravity(0, 0)
physics.setDrawMode("hybrid")

display.setStatusBar(display.HiddenStatusBar)

local stage = display.getCurrentStage()

local width = 100
local height = width*math.sqrt(3)/2
local centroidX = height/3
local centroidY = width/2
local radius = height - centroidX
local circle = display.newCircle(0, 0, radius)
circle:setFillColor(0, 0, 0)
circle.strokeWidth = 1
circle.x = stage.width/2
circle.y = stage.height/2

local triangle = display.newLine(0, 0, -centroidX,-centroidY)
triangle:append(radius, 0)
triangle:append(-centroidX, centroidY)
triangle:append(-centroidX, -centroidY)
triangle.x = circle.x
triangle.y = circle.y
physics.addBody(triangle, { shape = { -centroidX, -centroidY, radius, 0,  -centroidX, centroidY} })

triangle:applyTorque(5)

timer.performWithDelay(1000/60, function()
--triangle:rotate(6)
end, 0)