In ΔDEF, the measure of ∠F=90°, the measure of ∠D=69°, and FD = 64 feet. Find the length of DE to the nearest tenth of a foot.

Determine whether the samples are independent or dependent. upper a data set includes the morning and evening temperature for the lasta data set includes the morning and evening temperature for the last 90 days.90 days.

To find the extreme values of a function f(x.y) on a curve x-x(t), y y(t), treat f as a function of the single variable t and use the chain rule to find where df/dt is zero. in any other single-variable case, the extreme values of f are then found among the values at the critical points (points where df/dt is zero or fails to exist), and endpoints of the parameter domain. find the absolute maximum and minimum values of the following function on the given curves. use the parametric equations x=2cos t, y 2 sin t functions: curves: i) the semicircle x4,y20 i) the quarter circle x2+y-4, x20, y20 b, g(x,y)=xy

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.