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Finding the Fourth Proportional to 77.91, 116.30 and 66.42

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Solution

The fourth proportional to 77.91, 116.30 and 66.42 is: 99.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.91 : 116.30 = 66.42 : x
  2. Step 2: Convert to fraction form
    77.91/116.30 = 66.42/x
  3. Step 3: Cross multiply
    77.91x = 116.30 × 66.42
  4. Step 4: Simplify right side
    77.91x = 7,724.65
  5. Step 5: Solve for x
    x = 7,724.65/77.91
  6. Step 6: Final answer
    x = 99.15

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.