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Finding the Fourth Proportional to 131.28, 181.12 and 78.79

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Solution

The fourth proportional to 131.28, 181.12 and 78.79 is: 108.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.28 : 181.12 = 78.79 : x
  2. Step 2: Convert to fraction form
    131.28/181.12 = 78.79/x
  3. Step 3: Cross multiply
    131.28x = 181.12 × 78.79
  4. Step 4: Simplify right side
    131.28x = 14,270.44
  5. Step 5: Solve for x
    x = 14,270.44/131.28
  6. Step 6: Final answer
    x = 108.70

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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.