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Finding the Fourth Proportional to 670.66, 925.36 and 390.85

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Solution

The fourth proportional to 670.66, 925.36 and 390.85 is: 539.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.66 : 925.36 = 390.85 : x
  2. Step 2: Convert to fraction form
    670.66/925.36 = 390.85/x
  3. Step 3: Cross multiply
    670.66x = 925.36 × 390.85
  4. Step 4: Simplify right side
    670.66x = 361,673.67
  5. Step 5: Solve for x
    x = 361,673.67/670.66
  6. Step 6: Final answer
    x = 539.28

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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.