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Finding the Fourth Proportional to 100.68, 138.91 and 59.21

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Solution

The fourth proportional to 100.68, 138.91 and 59.21 is: 81.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.68 : 138.91 = 59.21 : x
  2. Step 2: Convert to fraction form
    100.68/138.91 = 59.21/x
  3. Step 3: Cross multiply
    100.68x = 138.91 × 59.21
  4. Step 4: Simplify right side
    100.68x = 8,224.86
  5. Step 5: Solve for x
    x = 8,224.86/100.68
  6. Step 6: Final answer
    x = 81.69

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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.