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Finding the Fourth Proportional to 717.12, 987.26 and 643.32

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Solution

The fourth proportional to 717.12, 987.26 and 643.32 is: 885.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.12 : 987.26 = 643.32 : x
  2. Step 2: Convert to fraction form
    717.12/987.26 = 643.32/x
  3. Step 3: Cross multiply
    717.12x = 987.26 × 643.32
  4. Step 4: Simplify right side
    717.12x = 635,120.89
  5. Step 5: Solve for x
    x = 635,120.89/717.12
  6. Step 6: Final answer
    x = 885.65

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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.