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Finding the Fourth Proportional to 123.12, 169.84 and 78.84

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Solution

The fourth proportional to 123.12, 169.84 and 78.84 is: 108.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.12 : 169.84 = 78.84 : x
  2. Step 2: Convert to fraction form
    123.12/169.84 = 78.84/x
  3. Step 3: Cross multiply
    123.12x = 169.84 × 78.84
  4. Step 4: Simplify right side
    123.12x = 13,390.19
  5. Step 5: Solve for x
    x = 13,390.19/123.12
  6. Step 6: Final answer
    x = 108.76

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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.