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Finding the Fourth Proportional to 345.78, 519.05 and 172.40

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Solution

The fourth proportional to 345.78, 519.05 and 172.40 is: 258.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    345.78 : 519.05 = 172.40 : x
  2. Step 2: Convert to fraction form
    345.78/519.05 = 172.40/x
  3. Step 3: Cross multiply
    345.78x = 519.05 × 172.40
  4. Step 4: Simplify right side
    345.78x = 89,480.76
  5. Step 5: Solve for x
    x = 89,480.76/345.78
  6. Step 6: Final answer
    x = 258.78

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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.