a. Triangle CDB and Triangle STR are similar by the SSS postulate. This postulate works because all 3 sides on both the triangles are congruent.
b. Because the triangles are similar by the SSS postulate, we know that all three sides are congruent to one another. We just need to find the common ratio. For side DC and TS, the ratio is 1.875:1. This applies to side BS and RS, so it must also apply to sides DB and TR. Since side TR is 14, side DB will be 1.875 times greater than 14, resulting in 26.25. Hope this helps!
