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Finding the Fourth Proportional to 217.29, 299.80 and 128.76

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Solution

The fourth proportional to 217.29, 299.80 and 128.76 is: 177.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    217.29 : 299.80 = 128.76 : x
  2. Step 2: Convert to fraction form
    217.29/299.80 = 128.76/x
  3. Step 3: Cross multiply
    217.29x = 299.80 × 128.76
  4. Step 4: Simplify right side
    217.29x = 38,602.25
  5. Step 5: Solve for x
    x = 38,602.25/217.29
  6. Step 6: Final answer
    x = 177.65

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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.