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Finding the Fourth Proportional to 100.14, 138.21 and 72.60

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Solution

The fourth proportional to 100.14, 138.21 and 72.60 is: 100.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.14 : 138.21 = 72.60 : x
  2. Step 2: Convert to fraction form
    100.14/138.21 = 72.60/x
  3. Step 3: Cross multiply
    100.14x = 138.21 × 72.60
  4. Step 4: Simplify right side
    100.14x = 10,033.77
  5. Step 5: Solve for x
    x = 10,033.77/100.14
  6. Step 6: Final answer
    x = 100.20

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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.