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Finding the Fourth Proportional to 69.88, 105 and 42.88

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Solution

The fourth proportional to 69.88, 105 and 42.88 is: 64.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.88 : 105 = 42.88 : x
  2. Step 2: Convert to fraction form
    69.88/105 = 42.88/x
  3. Step 3: Cross multiply
    69.88x = 105 × 42.88
  4. Step 4: Simplify right side
    69.88x = 4,502.40
  5. Step 5: Solve for x
    x = 4,502.40/69.88
  6. Step 6: Final answer
    x = 64.43

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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.