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Finding the Fourth Proportional to 90.61, 135.84 and 47.28

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Solution

The fourth proportional to 90.61, 135.84 and 47.28 is: 70.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.61 : 135.84 = 47.28 : x
  2. Step 2: Convert to fraction form
    90.61/135.84 = 47.28/x
  3. Step 3: Cross multiply
    90.61x = 135.84 × 47.28
  4. Step 4: Simplify right side
    90.61x = 6,422.52
  5. Step 5: Solve for x
    x = 6,422.52/90.61
  6. Step 6: Final answer
    x = 70.88

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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.