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Finding the Fourth Proportional to 670.42, 925.05 and 390.61

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Solution

The fourth proportional to 670.42, 925.05 and 390.61 is: 538.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.42 : 925.05 = 390.61 : x
  2. Step 2: Convert to fraction form
    670.42/925.05 = 390.61/x
  3. Step 3: Cross multiply
    670.42x = 925.05 × 390.61
  4. Step 4: Simplify right side
    670.42x = 361,333.78
  5. Step 5: Solve for x
    x = 361,333.78/670.42
  6. Step 6: Final answer
    x = 538.97

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.