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Finding the Fourth Proportional to 216.61, 298.81 and 128.06

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Solution

The fourth proportional to 216.61, 298.81 and 128.06 is: 176.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.61 : 298.81 = 128.06 : x
  2. Step 2: Convert to fraction form
    216.61/298.81 = 128.06/x
  3. Step 3: Cross multiply
    216.61x = 298.81 × 128.06
  4. Step 4: Simplify right side
    216.61x = 38,265.40
  5. Step 5: Solve for x
    x = 38,265.40/216.61
  6. Step 6: Final answer
    x = 176.66

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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.