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Finding the Fourth Proportional to 217.70, 300.45 and 129.21

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Solution

The fourth proportional to 217.70, 300.45 and 129.21 is: 178.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    217.70 : 300.45 = 129.21 : x
  2. Step 2: Convert to fraction form
    217.70/300.45 = 129.21/x
  3. Step 3: Cross multiply
    217.70x = 300.45 × 129.21
  4. Step 4: Simplify right side
    217.70x = 38,820.50
  5. Step 5: Solve for x
    x = 38,820.50/217.70
  6. Step 6: Final answer
    x = 178.32

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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.