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Finding the Fourth Proportional to 76.87, 106.19 and 66.70

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Solution

The fourth proportional to 76.87, 106.19 and 66.70 is: 92.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.87 : 106.19 = 66.70 : x
  2. Step 2: Convert to fraction form
    76.87/106.19 = 66.70/x
  3. Step 3: Cross multiply
    76.87x = 106.19 × 66.70
  4. Step 4: Simplify right side
    76.87x = 7,082.87
  5. Step 5: Solve for x
    x = 7,082.87/76.87
  6. Step 6: Final answer
    x = 92.14

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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.