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Finding the Fourth Proportional to 68.79, 102.57 and 66.90

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Solution

The fourth proportional to 68.79, 102.57 and 66.90 is: 99.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.79 : 102.57 = 66.90 : x
  2. Step 2: Convert to fraction form
    68.79/102.57 = 66.90/x
  3. Step 3: Cross multiply
    68.79x = 102.57 × 66.90
  4. Step 4: Simplify right side
    68.79x = 6,861.93
  5. Step 5: Solve for x
    x = 6,861.93/68.79
  6. Step 6: Final answer
    x = 99.75

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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.