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Finding the Fourth Proportional to 90.70, 135.85 and 47.90

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Solution

The fourth proportional to 90.70, 135.85 and 47.90 is: 71.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.70 : 135.85 = 47.90 : x
  2. Step 2: Convert to fraction form
    90.70/135.85 = 47.90/x
  3. Step 3: Cross multiply
    90.70x = 135.85 × 47.90
  4. Step 4: Simplify right side
    90.70x = 6,507.22
  5. Step 5: Solve for x
    x = 6,507.22/90.70
  6. Step 6: Final answer
    x = 71.74

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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.