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Finding the Fourth Proportional to 216.56, 298.76 and 129.21

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Solution

The fourth proportional to 216.56, 298.76 and 129.21 is: 178.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.56 : 298.76 = 129.21 : x
  2. Step 2: Convert to fraction form
    216.56/298.76 = 129.21/x
  3. Step 3: Cross multiply
    216.56x = 298.76 × 129.21
  4. Step 4: Simplify right side
    216.56x = 38,602.13
  5. Step 5: Solve for x
    x = 38,602.13/216.56
  6. Step 6: Final answer
    x = 178.26

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.