Answer:
The length of PR is 15.8 cm
Step-by-step explanation:
We will solve the question using the cosine rule
In ΔPQR
∵ (PR)² = (PQ)² + (RQ)² - 2(PQ)(RQ)(cos∠Q)
∵ PQ = 17.8 cm
∵ RQ = 26.3 cm
∵ m∠Q = 36°
→ Substitute them in the rule above
∵ (PR)² = (17.8)² + (26.3)² - 2(17.8)(26.3)(cos36)
∴ (PR)² = 316.84 + 691.69 - 936.28(cos36)
∴ (PR)² = 251.0635685
→ Take √ for both sides
∴ PR = 15.8449856
→ Correct it to 3 significant figures
∴ PR = 15.8 cm
∴ The length of PR is 15.8 cm
