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Finding the Fourth Proportional to 932.40, 1,398.60 and 640.80

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Solution

The fourth proportional to 932.40, 1,398.60 and 640.80 is: 961.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    932.40 : 1,398.60 = 640.80 : x
  2. Step 2: Convert to fraction form
    932.40/1,398.60 = 640.80/x
  3. Step 3: Cross multiply
    932.40x = 1,398.60 × 640.80
  4. Step 4: Simplify right side
    932.40x = 896,222.88
  5. Step 5: Solve for x
    x = 896,222.88/932.40
  6. Step 6: Final answer
    x = 961.20

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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.