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Finding the Fourth Proportional to 210.72, 315.78 and 129.33

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Solution

The fourth proportional to 210.72, 315.78 and 129.33 is: 193.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.72 : 315.78 = 129.33 : x
  2. Step 2: Convert to fraction form
    210.72/315.78 = 129.33/x
  3. Step 3: Cross multiply
    210.72x = 315.78 × 129.33
  4. Step 4: Simplify right side
    210.72x = 40,839.83
  5. Step 5: Solve for x
    x = 40,839.83/210.72
  6. Step 6: Final answer
    x = 193.81

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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.