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Finding the Fourth Proportional to 90.17, 135.05 and 77.68

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Solution

The fourth proportional to 90.17, 135.05 and 77.68 is: 116.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.17 : 135.05 = 77.68 : x
  2. Step 2: Convert to fraction form
    90.17/135.05 = 77.68/x
  3. Step 3: Cross multiply
    90.17x = 135.05 × 77.68
  4. Step 4: Simplify right side
    90.17x = 10,490.68
  5. Step 5: Solve for x
    x = 10,490.68/90.17
  6. Step 6: Final answer
    x = 116.34

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.