Chapter 3 - Radian Measure and the Unit Circle - Section 3.3 The Unit Circle and Circular Functions - 3.3 Exercises - Page 119: 86f

$12.2^{\circ}$ F

Since October $31$ is Day $304$, we substitute $x=304$ into the following equation and solve using a calculator: $T(x)=37\sin[\frac{2\pi}{365}(x-101)]+25$ $T(x)=37\sin[\frac{2\pi}{365}(304-101)]+25$ $T(x)=37\sin[\frac{2\pi}{365}(203)]+25$ $T(x)=37\sin[3.494]+25$ $T(x)=37(-0.3452)+25$ $T(x)=-12.79+25$ $T(x)=12.21\approx12.2^{\circ}$ F