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Finding the Fourth Proportional to 1,128.78, 1,692.90 and 398.34

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Solution

The fourth proportional to 1,128.78, 1,692.90 and 398.34 is: 597.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,128.78 : 1,692.90 = 398.34 : x
  2. Step 2: Convert to fraction form
    1,128.78/1,692.90 = 398.34/x
  3. Step 3: Cross multiply
    1,128.78x = 1,692.90 × 398.34
  4. Step 4: Simplify right side
    1,128.78x = 674,349.79
  5. Step 5: Solve for x
    x = 674,349.79/1,128.78
  6. Step 6: Final answer
    x = 597.41

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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.