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Finding the Fourth Proportional to 101, 139.23 and 81.40

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Solution

The fourth proportional to 101, 139.23 and 81.40 is: 112.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    101 : 139.23 = 81.40 : x
  2. Step 2: Convert to fraction form
    101/139.23 = 81.40/x
  3. Step 3: Cross multiply
    101x = 139.23 × 81.40
  4. Step 4: Simplify right side
    101x = 11,333.32
  5. Step 5: Solve for x
    x = 11,333.32/101
  6. Step 6: Final answer
    x = 112.21

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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.