Imagine right triangle with first leg to be the Chad length and second leg to be the Chad's shadow. Second leg has length 14.3 ft and since the straight-line distance from the top of Chad’s head to the end of the shadow creates a 23° angle with the ground, you could consider the trigonmetric function
[tex]\tan 23^{\circ}= \dfrac{\text{Chad's length}}{\text{Chad's shadow length}} [/tex],
then [tex]\tan 23^{\circ}= \dfrac{\text{Chad's length}}{14.3}, \\ \text{Chad's length}=14.3\cdot \tan 23^{\circ}=6.1[/tex].