Question Number 33676 by NECx last updated on 21/Apr/18
$${How}\:{fast}\:{is}\:{the}\:{height}\:{of}\:{a}\:{balloon} \\ $$$${changing}\:{when}\:\mathrm{500}{m}\:{away}\:{at}\:{an} \\ $$$${angle}\:{of}\:\pi/\mathrm{4}\:{rad}\:{and}\:{the}\:{angle}\:{is} \\ $$$${increasing}\:{by}\:\mathrm{0}.\mathrm{2}{rad}/{min} \\ $$