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Finding the Fourth Proportional to 613.55, 918.30 and 431.30

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Solution

The fourth proportional to 613.55, 918.30 and 431.30 is: 645.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    613.55 : 918.30 = 431.30 : x
  2. Step 2: Convert to fraction form
    613.55/918.30 = 431.30/x
  3. Step 3: Cross multiply
    613.55x = 918.30 × 431.30
  4. Step 4: Simplify right side
    613.55x = 396,062.79
  5. Step 5: Solve for x
    x = 396,062.79/613.55
  6. Step 6: Final answer
    x = 645.53

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.