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Finding the Fourth Proportional to 90.20, 135 and 64.42

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Solution

The fourth proportional to 90.20, 135 and 64.42 is: 96.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.20 : 135 = 64.42 : x
  2. Step 2: Convert to fraction form
    90.20/135 = 64.42/x
  3. Step 3: Cross multiply
    90.20x = 135 × 64.42
  4. Step 4: Simplify right side
    90.20x = 8,696.70
  5. Step 5: Solve for x
    x = 8,696.70/90.20
  6. Step 6: Final answer
    x = 96.42

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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.