45
Find two numbers such that their mean proportional is 18 and the third proportional to them is 144.
- A6 and 42
- B9 and 36
- C3 and 18
- D6 and 12
Answer not set
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0
CCommunity
Let the numbers are x and y,
Mean proportional = √xy = 18
⇒ xy = 324 ---- (1)
Third proportional = y2/x = 144
⇒ y2 = 144x ---- (2)
Putting the value of x from this in 1st equation,
⇒ y3/144 = 324
⇒ y3 = 324 × 144
⇒ y3 = 18 × 18 × 18 × 8
⇒ y = 18 × 2
⇒ y = 36 and x = 324/36 = 9
∴ Two numbers are 9 and 36.
Mean proportional = √xy = 18
⇒ xy = 324 ---- (1)
Third proportional = y2/x = 144
⇒ y2 = 144x ---- (2)
Putting the value of x from this in 1st equation,
⇒ y3/144 = 324
⇒ y3 = 324 × 144
⇒ y3 = 18 × 18 × 18 × 8
⇒ y = 18 × 2
⇒ y = 36 and x = 324/36 = 9
∴ Two numbers are 9 and 36.
0
CCommunity
Hi friends, it's answer is 9 and 36. Surely!!!!