Chapter 10 - Radical Expressions and Equations - 10-1 The Pythagorean Theorem - Practice and Problem-Solving Exercises - Page 603: 14

a=1.2

The Pythagorean Theorem states that for a right triangle, $a^{2} +b^{2} = c^{2}$. Thus, we plug in the values given for a, b, or c, and then we use these values to find the missing value: $a^{2} + 3.5^{2} =3.7^{2} \\\\ a^{2} +12.25=13.69 \\\\ a^{2} =1.44 \\\\ a=1.2$