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Finding the Fourth Proportional to 67.29, 91.70 and 65.90

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Solution

The fourth proportional to 67.29, 91.70 and 65.90 is: 89.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    67.29 : 91.70 = 65.90 : x
  2. Step 2: Convert to fraction form
    67.29/91.70 = 65.90/x
  3. Step 3: Cross multiply
    67.29x = 91.70 × 65.90
  4. Step 4: Simplify right side
    67.29x = 6,042.24
  5. Step 5: Solve for x
    x = 6,042.24/67.29
  6. Step 6: Final answer
    x = 89.79

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Why These Related Problems?

These problems maintain the same ratio (1.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.