activityInfo.activeMinutesWeek.toFloat

Why cannot I do this?

goalProgress = activityInfo.activeMinutesWeek.toFloat() / activityInfo.activeMinutesWeekGoal.toFloat() * 100;

I get...

Could not find symbol toFloat.Failed invoking <symbol>Symbol Not Found Error

This is OK

activityInfo.activeMinutesWeekGoal.toFloat()

This isn't

activityInfo.activeMinutesWeek.toFloat()