Answer:
x = 5
Step-by-step explanation:
a² + b² = c²
x² + 12² = 13²
x² + 144 = 169
x² = 169 - 144
x² = 25

x = 5
14.4, if my calculator was correct
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Here's a website that might help
506,211+424,809=931,020 sum means add hope this helps
3.02*6.10 will give you the answer quite simple