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Finding the Fourth Proportional to 708.68, 975.78 and 643.88

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Solution

The fourth proportional to 708.68, 975.78 and 643.88 is: 886.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.68 : 975.78 = 643.88 : x
  2. Step 2: Convert to fraction form
    708.68/975.78 = 643.88/x
  3. Step 3: Cross multiply
    708.68x = 975.78 × 643.88
  4. Step 4: Simplify right side
    708.68x = 628,285.23
  5. Step 5: Solve for x
    x = 628,285.23/708.68
  6. Step 6: Final answer
    x = 886.56

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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.