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Finding the Fourth Proportional to 90.18, 135.30 and 61.21

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Solution

The fourth proportional to 90.18, 135.30 and 61.21 is: 91.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.18 : 135.30 = 61.21 : x
  2. Step 2: Convert to fraction form
    90.18/135.30 = 61.21/x
  3. Step 3: Cross multiply
    90.18x = 135.30 × 61.21
  4. Step 4: Simplify right side
    90.18x = 8,281.71
  5. Step 5: Solve for x
    x = 8,281.71/90.18
  6. Step 6: Final answer
    x = 91.84

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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.