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Finding the Fourth Proportional to 90.87, 124.56 and 89.28

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Solution

The fourth proportional to 90.87, 124.56 and 89.28 is: 122.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.87 : 124.56 = 89.28 : x
  2. Step 2: Convert to fraction form
    90.87/124.56 = 89.28/x
  3. Step 3: Cross multiply
    90.87x = 124.56 × 89.28
  4. Step 4: Simplify right side
    90.87x = 11,120.72
  5. Step 5: Solve for x
    x = 11,120.72/90.87
  6. Step 6: Final answer
    x = 122.39

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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.