order from least to greatest:
$\sqrt{21}$, $\sqrt[3]{27}$, $-\sqrt{64}$, $\sqrt[4]{25}$, $\sqrt{40}$, $-\sqrt[3]{81}$
-cube root 81, -square root 64, quad-root 25, cube root 27, square rroot 21, square root 40.
-sqrt (64) = -8
-cube root ( 81) = -3 cube root (3) ≈ - 4.326
4throot (25) ≈ 2.236
cube root (27) = 3
sqrt (21) ≈ 4.58
sqrt (40) = 2sqrt (10) ≈ 6.32
