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Finding the Fourth Proportional to 90.65, 135.31 and 84.57

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Solution

The fourth proportional to 90.65, 135.31 and 84.57 is: 126.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.65 : 135.31 = 84.57 : x
  2. Step 2: Convert to fraction form
    90.65/135.31 = 84.57/x
  3. Step 3: Cross multiply
    90.65x = 135.31 × 84.57
  4. Step 4: Simplify right side
    90.65x = 11,442.96
  5. Step 5: Solve for x
    x = 11,442.96/90.65
  6. Step 6: Final answer
    x = 126.24

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.