function roofarea()

{

var p=parseFloat(document.roofcalc.pitch.value)

var w=parseFloat(document.roofcalc.width.value)

var l=parseFloat(document.roofcalc.lengths.value)

var d=p/12

var f=d*d

var g=f+1

var h=Math.sqrt(g)

var ans=h*l*w

document.roofcalc.answer.value = ans

var r_sht=Math.ceil(ans/32)

document.roofcalc.sheets_r.value = r_sht

var sht_cst = document.roofcalc.sheet_c.value

var cost = r_sht * sht_cst

document.roofcalc.proj_cost.value = cost

}