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Finding the Fourth Proportional to 807.98, 1,117.25 and 641.90

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Solution

The fourth proportional to 807.98, 1,117.25 and 641.90 is: 887.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    807.98 : 1,117.25 = 641.90 : x
  2. Step 2: Convert to fraction form
    807.98/1,117.25 = 641.90/x
  3. Step 3: Cross multiply
    807.98x = 1,117.25 × 641.90
  4. Step 4: Simplify right side
    807.98x = 717,162.78
  5. Step 5: Solve for x
    x = 717,162.78/807.98
  6. Step 6: Final answer
    x = 887.60

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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.