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Finding the Fourth Proportional to 217.34, 299.90 and 128.80

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Solution

The fourth proportional to 217.34, 299.90 and 128.80 is: 177.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    217.34 : 299.90 = 128.80 : x
  2. Step 2: Convert to fraction form
    217.34/299.90 = 128.80/x
  3. Step 3: Cross multiply
    217.34x = 299.90 × 128.80
  4. Step 4: Simplify right side
    217.34x = 38,627.12
  5. Step 5: Solve for x
    x = 38,627.12/217.34
  6. Step 6: Final answer
    x = 177.73

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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.