i neeed help please i did not understand it

Answer:
[tex]15.71cm[/tex]
Step-by-step explanation:
[tex]10 \: \: years = 3.142 \\ 50 \: years = x \\ \\ 10 = 3.142 \\ 50 = x \\ cross \: \: multiply \\ 10x = 50 \times 3.142 \\ 10x = 157.1 \\ x = 15.71cm[/tex]
hope this helps you
can I have the brainliest please?