Hello, jwein4492!
Given: .$\displaystyle \Delta RTS \sim \Delta RDC$
Prove that: .$\displaystyle CD \parallel ST$ Code:
R
*
* *
* *
* *
T * * * * * S
* *
D * * * * * C
$\displaystyle (1)\;\;\Delta RTS \sim \Delta RDC\qquad \text{Given}$
$\displaystyle (2)\;\;\angle RTS = \angle RDC\qquad\text{Corres. angles of similar triangles are equal}$
$\displaystyle (3)\;\;\therefore \;ST \parallel CD\qquad\qquad\text{If two lines are cut by a transversal}$ $\displaystyle \text{ and their corresponding}$
. . . . . . . . . . . . . . . .$\displaystyle \text{angles are equal, the two lines are parallel.}$