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Finding the Fourth Proportional to 90.78, 124.46 and 89.14

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Solution

The fourth proportional to 90.78, 124.46 and 89.14 is: 122.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.78 : 124.46 = 89.14 : x
  2. Step 2: Convert to fraction form
    90.78/124.46 = 89.14/x
  3. Step 3: Cross multiply
    90.78x = 124.46 × 89.14
  4. Step 4: Simplify right side
    90.78x = 11,094.28
  5. Step 5: Solve for x
    x = 11,094.28/90.78
  6. Step 6: Final answer
    x = 122.21

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.