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Finding the Fourth Proportional to 862.40, 1,188.88 and 640.96

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Solution

The fourth proportional to 862.40, 1,188.88 and 640.96 is: 883.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    862.40 : 1,188.88 = 640.96 : x
  2. Step 2: Convert to fraction form
    862.40/1,188.88 = 640.96/x
  3. Step 3: Cross multiply
    862.40x = 1,188.88 × 640.96
  4. Step 4: Simplify right side
    862.40x = 762,026.64
  5. Step 5: Solve for x
    x = 762,026.64/862.40
  6. Step 6: Final answer
    x = 883.61

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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.