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Finding the Fourth Proportional to 100.86, 139.50 and 99.92

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Solution

The fourth proportional to 100.86, 139.50 and 99.92 is: 138.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.86 : 139.50 = 99.92 : x
  2. Step 2: Convert to fraction form
    100.86/139.50 = 99.92/x
  3. Step 3: Cross multiply
    100.86x = 139.50 × 99.92
  4. Step 4: Simplify right side
    100.86x = 13,938.14
  5. Step 5: Solve for x
    x = 13,938.14/100.86
  6. Step 6: Final answer
    x = 138.19

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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.