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Finding the Fourth Proportional to 216.38, 298.50 and 128.99

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Solution

The fourth proportional to 216.38, 298.50 and 128.99 is: 177.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.38 : 298.50 = 128.99 : x
  2. Step 2: Convert to fraction form
    216.38/298.50 = 128.99/x
  3. Step 3: Cross multiply
    216.38x = 298.50 × 128.99
  4. Step 4: Simplify right side
    216.38x = 38,503.52
  5. Step 5: Solve for x
    x = 38,503.52/216.38
  6. Step 6: Final answer
    x = 177.94

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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.