Question

Please help me with both questions thank you.

Answer 1

The First question would be, Transitive Property.

Answer 2

if RS = ST and ST = TU, then RS = TU
this is the transitive property which states : if a = b, and b = c, then a = c
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there is a pattern....light, medium, dark, light, medium, dark....etc
so the 10th item is : the lightest triangle...1st answer choice