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Finding the Fourth Proportional to 100.32, 138.48 and 72.81

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Solution

The fourth proportional to 100.32, 138.48 and 72.81 is: 100.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.32 : 138.48 = 72.81 : x
  2. Step 2: Convert to fraction form
    100.32/138.48 = 72.81/x
  3. Step 3: Cross multiply
    100.32x = 138.48 × 72.81
  4. Step 4: Simplify right side
    100.32x = 10,082.73
  5. Step 5: Solve for x
    x = 10,082.73/100.32
  6. Step 6: Final answer
    x = 100.51

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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.