Given: RT―≅TV― and ST―≅TU― Prove: RSVU is a parallelogram. Open image in full-screen view What is the missing statement in step 4?

The diagonals intersect at T, so ∠RTS and ∠VTU are vertical angles, as are ∠RTU and ∠VTS. With RT ≅ TV and ST ≅ TU, SAS gives △RTS ≅ △VTU and △RTU ≅ △VTS. Thus the missing statement is choice B.

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