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Finding the Fourth Proportional to 989.46, 1,364.88 and 640.15

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Solution

The fourth proportional to 989.46, 1,364.88 and 640.15 is: 883.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.46 : 1,364.88 = 640.15 : x
  2. Step 2: Convert to fraction form
    989.46/1,364.88 = 640.15/x
  3. Step 3: Cross multiply
    989.46x = 1,364.88 × 640.15
  4. Step 4: Simplify right side
    989.46x = 873,726.92
  5. Step 5: Solve for x
    x = 873,726.92/989.46
  6. Step 6: Final answer
    x = 883.03

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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.