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Finding the Fourth Proportional to 76.90, 115.33 and 42.67

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Solution

The fourth proportional to 76.90, 115.33 and 42.67 is: 63.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.90 : 115.33 = 42.67 : x
  2. Step 2: Convert to fraction form
    76.90/115.33 = 42.67/x
  3. Step 3: Cross multiply
    76.90x = 115.33 × 42.67
  4. Step 4: Simplify right side
    76.90x = 4,921.13
  5. Step 5: Solve for x
    x = 4,921.13/76.90
  6. Step 6: Final answer
    x = 63.99

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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.