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Finding the Fourth Proportional to 216.13, 298.25 and 128.81

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Solution

The fourth proportional to 216.13, 298.25 and 128.81 is: 177.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.13 : 298.25 = 128.81 : x
  2. Step 2: Convert to fraction form
    216.13/298.25 = 128.81/x
  3. Step 3: Cross multiply
    216.13x = 298.25 × 128.81
  4. Step 4: Simplify right side
    216.13x = 38,417.58
  5. Step 5: Solve for x
    x = 38,417.58/216.13
  6. Step 6: Final answer
    x = 177.75

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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.