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Finding the Fourth Proportional to 766.56, 1,057.68 and 642.72

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Solution

The fourth proportional to 766.56, 1,057.68 and 642.72 is: 886.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    766.56 : 1,057.68 = 642.72 : x
  2. Step 2: Convert to fraction form
    766.56/1,057.68 = 642.72/x
  3. Step 3: Cross multiply
    766.56x = 1,057.68 × 642.72
  4. Step 4: Simplify right side
    766.56x = 679,792.09
  5. Step 5: Solve for x
    x = 679,792.09/766.56
  6. Step 6: Final answer
    x = 886.81

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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.