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Finding the Fourth Proportional to 641.50, 885.70 and 491.85

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Solution

The fourth proportional to 641.50, 885.70 and 491.85 is: 679.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.50 : 885.70 = 491.85 : x
  2. Step 2: Convert to fraction form
    641.50/885.70 = 491.85/x
  3. Step 3: Cross multiply
    641.50x = 885.70 × 491.85
  4. Step 4: Simplify right side
    641.50x = 435,631.55
  5. Step 5: Solve for x
    x = 435,631.55/641.50
  6. Step 6: Final answer
    x = 679.08

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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.