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Finding the Fourth Proportional to 112.85, 169.08 and 78.55

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Solution

The fourth proportional to 112.85, 169.08 and 78.55 is: 117.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    112.85 : 169.08 = 78.55 : x
  2. Step 2: Convert to fraction form
    112.85/169.08 = 78.55/x
  3. Step 3: Cross multiply
    112.85x = 169.08 × 78.55
  4. Step 4: Simplify right side
    112.85x = 13,281.14
  5. Step 5: Solve for x
    x = 13,281.14/112.85
  6. Step 6: Final answer
    x = 117.68

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.