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Finding the Fourth Proportional to 76.43, 105.42 and 64.88

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Solution

The fourth proportional to 76.43, 105.42 and 64.88 is: 89.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.43 : 105.42 = 64.88 : x
  2. Step 2: Convert to fraction form
    76.43/105.42 = 64.88/x
  3. Step 3: Cross multiply
    76.43x = 105.42 × 64.88
  4. Step 4: Simplify right side
    76.43x = 6,839.65
  5. Step 5: Solve for x
    x = 6,839.65/76.43
  6. Step 6: Final answer
    x = 89.49

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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.