Can someone help me with part b on this question please?

9514 1404 393
Answer:
12.0 cm
Step-by-step explanation:
The Pythagorean theorem applies:
(12 cm)² +b² = (17 cm)²
b² = (289 -144) cm² = 145 cm²
b = √145 cm ≈ 12.04 cm
b ≈ 12.0 cm . . . . rounded to 1 decimal place