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Finding the Fourth Proportional to 90.78, 124.47 and 90.69

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Solution

The fourth proportional to 90.78, 124.47 and 90.69 is: 124.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.78 : 124.47 = 90.69 : x
  2. Step 2: Convert to fraction form
    90.78/124.47 = 90.69/x
  3. Step 3: Cross multiply
    90.78x = 124.47 × 90.69
  4. Step 4: Simplify right side
    90.78x = 11,288.18
  5. Step 5: Solve for x
    x = 11,288.18/90.78
  6. Step 6: Final answer
    x = 124.35

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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.