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Finding the Fourth Proportional to 688.61, 1,031.98 and 380

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Solution

The fourth proportional to 688.61, 1,031.98 and 380 is: 569.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.61 : 1,031.98 = 380 : x
  2. Step 2: Convert to fraction form
    688.61/1,031.98 = 380/x
  3. Step 3: Cross multiply
    688.61x = 1,031.98 × 380
  4. Step 4: Simplify right side
    688.61x = 392,152.40
  5. Step 5: Solve for x
    x = 392,152.40/688.61
  6. Step 6: Final answer
    x = 569.48

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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.