Final answer:
To find the variable b and the length of side SR, set the expressions 7b+8 and 11b-12 equal to each other, solve for b, which is 5, and then substitute this into the expression for SR to get the length of 43.
Step-by-step explanation:
The student's question involves determining the value of the variable b and the length of side SR given that triangles △STR and △LMN are congruent with SR and LN as corresponding sides. According to the given information, SR equals 7b+8 and LN equals 11b−12. Since the triangles are congruent, these two expressions must be equal.
To find the value of b, set the expressions equal to each other:
Now, solve for b:
- 7b + 8 = 11b − 12
- 8 + 12 = 11b − 7b
- 20 = 4b
- b = 5
Substitute b = 5 into the expression for SR to find its length:
- SR = 7(5) + 8
- SR = 35 + 8
- SR = 43
Therefore, the correct answer is (b) b = 5 and SR = 43.