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Finding the Fourth Proportional to 90.64, 136.02 and 69.40

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Solution

The fourth proportional to 90.64, 136.02 and 69.40 is: 104.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.64 : 136.02 = 69.40 : x
  2. Step 2: Convert to fraction form
    90.64/136.02 = 69.40/x
  3. Step 3: Cross multiply
    90.64x = 136.02 × 69.40
  4. Step 4: Simplify right side
    90.64x = 9,439.79
  5. Step 5: Solve for x
    x = 9,439.79/90.64
  6. Step 6: Final answer
    x = 104.15

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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.