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Finding the Fourth Proportional to 683.64, 939.60 and 664.20

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Solution

The fourth proportional to 683.64, 939.60 and 664.20 is: 912.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    683.64 : 939.60 = 664.20 : x
  2. Step 2: Convert to fraction form
    683.64/939.60 = 664.20/x
  3. Step 3: Cross multiply
    683.64x = 939.60 × 664.20
  4. Step 4: Simplify right side
    683.64x = 624,082.32
  5. Step 5: Solve for x
    x = 624,082.32/683.64
  6. Step 6: Final answer
    x = 912.88

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.