Answer
26. 92 inches
Work Step by Step
1. Split an isosceles triangle into two equal right triangles, with angle $38.12^{\circ}$ and adjacent side $21.18 in$ (halved base of the isosceles triangle )
2. To find x (hypotenuse) use definition of trig function cosine
$\cos 38.12^{\circ} = \frac{21.18}{x}$
$x\approx 26.92$ [4 significant figures as it is in a given adjacent side]
