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Finding the Fourth Proportional to 76.71, 115.11 and 70.91

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Solution

The fourth proportional to 76.71, 115.11 and 70.91 is: 106.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.71 : 115.11 = 70.91 : x
  2. Step 2: Convert to fraction form
    76.71/115.11 = 70.91/x
  3. Step 3: Cross multiply
    76.71x = 115.11 × 70.91
  4. Step 4: Simplify right side
    76.71x = 8,161.87
  5. Step 5: Solve for x
    x = 8,161.87/76.71
  6. Step 6: Final answer
    x = 106.40

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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.