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Finding the Fourth Proportional to 123.96, 171.06 and 72.21

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Solution

The fourth proportional to 123.96, 171.06 and 72.21 is: 99.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.96 : 171.06 = 72.21 : x
  2. Step 2: Convert to fraction form
    123.96/171.06 = 72.21/x
  3. Step 3: Cross multiply
    123.96x = 171.06 × 72.21
  4. Step 4: Simplify right side
    123.96x = 12,352.24
  5. Step 5: Solve for x
    x = 12,352.24/123.96
  6. Step 6: Final answer
    x = 99.65

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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.