I need help with number 3
1 answer:
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Focus on triangles DFC and DFE:
- They are both right triangles because DF is perpendicular to EC
- DC=DE
- DF is a common side
So, the two triangles are congruent. It follows that CF=FE, and in particular
And since x=3, the length of EF is
To change 0.005 to a percent, just multiply by 100. 
Therefore, your answer would be 0.5%
Therefore, your answer would be 0.5%