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Finding the Fourth Proportional to 76.96, 115.20 and 70.80

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Solution

The fourth proportional to 76.96, 115.20 and 70.80 is: 105.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.96 : 115.20 = 70.80 : x
  2. Step 2: Convert to fraction form
    76.96/115.20 = 70.80/x
  3. Step 3: Cross multiply
    76.96x = 115.20 × 70.80
  4. Step 4: Simplify right side
    76.96x = 8,156.16
  5. Step 5: Solve for x
    x = 8,156.16/76.96
  6. Step 6: Final answer
    x = 105.98

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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.