DE^2 = 1 + 16 = 17.
<span>EF^2 = 16 + 1 = 17. </span>
<span>DF^2 = 9 + 25 = 34. </span>
<span>Since (DE)^2 + (EF)^2 = (DF)^2,
</span><span> angle E is 90 degrees.
</span><span> DF must be the hypotenuse
</span>see attachment below
<span>EF^2 = 16 + 1 = 17. </span>
<span>DF^2 = 9 + 25 = 34. </span>
<span>Since (DE)^2 + (EF)^2 = (DF)^2,
</span><span> angle E is 90 degrees.
</span><span> DF must be the hypotenuse
</span>see attachment below