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Finding the Fourth Proportional to 645.55, 891.98 and 480.31

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Solution

The fourth proportional to 645.55, 891.98 and 480.31 is: 663.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.55 : 891.98 = 480.31 : x
  2. Step 2: Convert to fraction form
    645.55/891.98 = 480.31/x
  3. Step 3: Cross multiply
    645.55x = 891.98 × 480.31
  4. Step 4: Simplify right side
    645.55x = 428,426.91
  5. Step 5: Solve for x
    x = 428,426.91/645.55
  6. Step 6: Final answer
    x = 663.66

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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.