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Finding the Fourth Proportional to 88.78, 122.40 and 66.91

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Solution

The fourth proportional to 88.78, 122.40 and 66.91 is: 92.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    88.78 : 122.40 = 66.91 : x
  2. Step 2: Convert to fraction form
    88.78/122.40 = 66.91/x
  3. Step 3: Cross multiply
    88.78x = 122.40 × 66.91
  4. Step 4: Simplify right side
    88.78x = 8,189.78
  5. Step 5: Solve for x
    x = 8,189.78/88.78
  6. Step 6: Final answer
    x = 92.25

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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.