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Finding the Fourth Proportional to 101.64, 139.94 and 87.78

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Solution

The fourth proportional to 101.64, 139.94 and 87.78 is: 120.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.64 : 139.94 = 87.78 : x
  2. Step 2: Convert to fraction form
    101.64/139.94 = 87.78/x
  3. Step 3: Cross multiply
    101.64x = 139.94 × 87.78
  4. Step 4: Simplify right side
    101.64x = 12,283.93
  5. Step 5: Solve for x
    x = 12,283.93/101.64
  6. Step 6: Final answer
    x = 120.86

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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.