Question 4 on this piece of paper that is his homework reads...
Triangle PQR ~ Triangle DEF.
Determine the length of DF
If PQ = 10cm, DE=5cm and PR=6cm.
Now a search of the net thank you Mr Google lets me know the the tilda sign ~ appears to mean "Similar"
And two triangles are similar if they gave the same corresponding angles but can have different sizes and rotation.
I suspect that just because someone writes
"Triangle PQR ~ Triangle DEF"
As I understand it, this does not mean that PQ actually equals DF and so on.
So depending on the rotation or definition of DEF, Then DF could be 3 or 8.3333 or something else.
So it seems to me that we need more info.
The challenge is over to you. Can someone answer this question or tell me definitively that it cant be answered.