Look at the figure shown below: a triangle rpq is shown. s is a point on side pr, and t is a point on side pq. points s and t are joined using a straight line. the length of ps is equal to 60, the length of sr is equal to x, the length of pt is equal to 48, and the length of tq is equal to 36. nora is writing statements as shown below to prove that if segment st is parallel to segment rq, then x = 45: statement reason 1. segment st is parallel to segment rq. given 2. angle qrs is congruent to angle tsp. corresponding angles formed by parallel lines and their transversal are congruent. 3. angle spt is congruent to angle rpq. reflexive property of angles 4. triangle spt is similar to triangle rpq. angle-angle similarity postulate 5. ? corresponding sides of similar triangles are in proportion. which equation can she use as statement 5?

a) 60: x = 48: (48 + 36)
b) 60 + x = 48 + 36
c) 60 − x = 48 − 36
d) 60: (60 + x) = 48: (48 + 36)