Question

What is the third proportional of 2√3 and 6√5?

• A. 50 √6
• B. 40 √3
• C. 20 √6
• D. 30 √3

Answer 1

Answer:

D. 30 √3

Solution: Concept used: The third proportional proportion is the second term of the mean terms. For example, if we have a ∶ b = c ∶ d, then the term ‘c’ is the third proportional to ‘a’ and ‘b’. Represented as: a : b ∷ b : c Calculation: Let the third proportion to 2√3 and 6√5 be x ⇒ 2√3/6√5 = 6√5/x ⇒ x = (6√5 × 6√5)/2√3 ⇒ x = 90/√3 = 30√3 ∴ The third proportional to 2√3 and 6√5 is 30√3.