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Finding the Fourth Proportional to 688.21, 1,031.30 and 542.31

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Solution

The fourth proportional to 688.21, 1,031.30 and 542.31 is: 812.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.21 : 1,031.30 = 542.31 : x
  2. Step 2: Convert to fraction form
    688.21/1,031.30 = 542.31/x
  3. Step 3: Cross multiply
    688.21x = 1,031.30 × 542.31
  4. Step 4: Simplify right side
    688.21x = 559,281.59
  5. Step 5: Solve for x
    x = 559,281.59/688.21
  6. Step 6: Final answer
    x = 812.66

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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.