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Finding the Fourth Proportional to 988.72, 1,363.98 and 639.52

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Solution

The fourth proportional to 988.72, 1,363.98 and 639.52 is: 882.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    988.72 : 1,363.98 = 639.52 : x
  2. Step 2: Convert to fraction form
    988.72/1,363.98 = 639.52/x
  3. Step 3: Cross multiply
    988.72x = 1,363.98 × 639.52
  4. Step 4: Simplify right side
    988.72x = 872,292.49
  5. Step 5: Solve for x
    x = 872,292.49/988.72
  6. Step 6: Final answer
    x = 882.24

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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.