Next, we {{CMD_93}}find equations{{CMD_94}} that relate relevant variables. Here we use the Pythagorean Theorem. {{MATH_95}} Note that {{MATH_96}} is a constant, and {{MATH_97}} and {{MATH_98}} are functions of time, {{MATH_99}}. We, then, {{CMD_100}}differentiate{{CMD_101}} both sides of the equation with respect to {{MATH_102}}, using implicit differentiation {{MATH_103}} Now, we {{CMD_104}}evaluate{{CMD_105}} all the quantities at the instant when {{MATH_106}}, noting that {{MATH_107}} and that {{MATH_108}}. Therefore, {{MATH_109}} We need to compute {{MATH_110}}, the length of the hypotenuse at the instant when {{MATH_111}}. Here we use the Pythagorean Theorem {{ENV_112}} So, we see that {{MATH_113}}, when {{MATH_114}}. {{CMD_115}} Then, we {{CMD_116}}solve{{CMD_117}} for the rate at the moment when {{MATH_118}},{{CMD_119}} {{ENV_120}} Therefore, the hypotenuse is growing at a rate of {{MATH_121}} m/s when both legs are {{MATH_122}} long. {{CMD_123}} {{CMD_124}}