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Finding the Fourth Proportional to 688.90, 1,031.85 and 424.55

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Solution

The fourth proportional to 688.90, 1,031.85 and 424.55 is: 635.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.90 : 1,031.85 = 424.55 : x
  2. Step 2: Convert to fraction form
    688.90/1,031.85 = 424.55/x
  3. Step 3: Cross multiply
    688.90x = 1,031.85 × 424.55
  4. Step 4: Simplify right side
    688.90x = 438,066.76
  5. Step 5: Solve for x
    x = 438,066.76/688.90
  6. Step 6: Final answer
    x = 635.90

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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.