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Finding the Fourth Proportional to 115.11, 158.86 and 78.21

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Solution

The fourth proportional to 115.11, 158.86 and 78.21 is: 107.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    115.11 : 158.86 = 78.21 : x
  2. Step 2: Convert to fraction form
    115.11/158.86 = 78.21/x
  3. Step 3: Cross multiply
    115.11x = 158.86 × 78.21
  4. Step 4: Simplify right side
    115.11x = 12,423.26
  5. Step 5: Solve for x
    x = 12,423.26/115.11
  6. Step 6: Final answer
    x = 107.93

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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.