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Finding the Fourth Proportional to 90.65, 124.24 and 87.91

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Solution

The fourth proportional to 90.65, 124.24 and 87.91 is: 120.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.65 : 124.24 = 87.91 : x
  2. Step 2: Convert to fraction form
    90.65/124.24 = 87.91/x
  3. Step 3: Cross multiply
    90.65x = 124.24 × 87.91
  4. Step 4: Simplify right side
    90.65x = 10,921.94
  5. Step 5: Solve for x
    x = 10,921.94/90.65
  6. Step 6: Final answer
    x = 120.48

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.