# Math Help - How do I prove that ST andCD are parallel?

1. ## How do I prove that ST andCD are parallel?

Prove that cd and st are parallel.

2. Hello, jwein4492!

Given: . $\Delta RTS \sim \Delta RDC$

Prove that: . $CD \parallel ST$
Code:
                         R
*
* *
*   *
*     *
T * * * * * S
*         *
D *  *  *  *  * C

$(1)\;\;\Delta RTS \sim \Delta RDC\qquad \text{Given}$

$(2)\;\;\angle RTS = \angle RDC\qquad\text{Corres. angles of similar triangles are equal}$

$(3)\;\;\therefore \;ST \parallel CD\qquad\qquad\text{If two lines are cut by a transversal}$ $\text{ and their corresponding}$
. . . . . . . . . . . . . . . . $\text{angles are equal, the two lines are parallel.}$