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Finding the Fourth Proportional to 210.80, 315.96 and 129.56

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Solution

The fourth proportional to 210.80, 315.96 and 129.56 is: 194.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.80 : 315.96 = 129.56 : x
  2. Step 2: Convert to fraction form
    210.80/315.96 = 129.56/x
  3. Step 3: Cross multiply
    210.80x = 315.96 × 129.56
  4. Step 4: Simplify right side
    210.80x = 40,935.78
  5. Step 5: Solve for x
    x = 40,935.78/210.80
  6. Step 6: Final answer
    x = 194.19

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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.