Answer:
Step-by-step explanation:

It's an equilateral triangle. The angles have measure 60°.
Therefore we have the equations:
6x + 6 = 60 <em>subtract 6 from both sides</em>
6x = 54 <em>divide both sides by 6</em>
x = 9
5y + 10 = 60 <em>subtract 10 from both sides</em>
5y = 50 <em>divide both sides by 5</em>
y = 10
Answer: 2cm/year
Step-by-step explanation:
1m = 100cm
200m = 20000cm
10,000years = 20,000cm
1 year = 20,000/10,000 = 2cm
It's rate is 2cm/year
Mhm just look for it on google