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Finding the Fourth Proportional to 101.24, 139.78 and 87.57

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Solution

The fourth proportional to 101.24, 139.78 and 87.57 is: 120.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.24 : 139.78 = 87.57 : x
  2. Step 2: Convert to fraction form
    101.24/139.78 = 87.57/x
  3. Step 3: Cross multiply
    101.24x = 139.78 × 87.57
  4. Step 4: Simplify right side
    101.24x = 12,240.53
  5. Step 5: Solve for x
    x = 12,240.53/101.24
  6. Step 6: Final answer
    x = 120.91

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.