Q. 2) In △DEF,DE=5 and EF=8. If the length of the third side is an integer, what is the greatest possible value for DF ?5+8=12
Triangle Inequality Theorem: We know that in any triangle, the sum of the lengths of any two sides must be greater than the length of the third side.
Applying Inequality to DE + EF: So, DE+EF>DF, which means 5+8>DF.
Calculating Upper Limit for DF: That gives us 13>DF.
Difference Inequality for EF−DE: But we also know that the difference of the lengths of any two sides must be less than the length of the third side.
Calculating Lower Limit for DF: So, EF−DE<DF, which means 8−5<DF.
Determining Range for DF: That gives us 3<DF.
Maximum Integer Value for DF: Therefore, DF must be greater than 3 and less than 13.
Maximum Integer Value for DF: Therefore, DF must be greater than 3 and less than 13. Since DF is an integer, the greatest possible integer value for DF is 12.
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