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Finding the Fourth Proportional to 210.47, 315.90 and 138.38

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Solution

The fourth proportional to 210.47, 315.90 and 138.38 is: 207.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.47 : 315.90 = 138.38 : x
  2. Step 2: Convert to fraction form
    210.47/315.90 = 138.38/x
  3. Step 3: Cross multiply
    210.47x = 315.90 × 138.38
  4. Step 4: Simplify right side
    210.47x = 43,712.66
  5. Step 5: Solve for x
    x = 43,712.66/210.47
  6. Step 6: Final answer
    x = 207.70

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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.