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Finding the Fourth Proportional to 988.69, 1,364.39 and 639.38

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Solution

The fourth proportional to 988.69, 1,364.39 and 639.38 is: 882.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    988.69 : 1,364.39 = 639.38 : x
  2. Step 2: Convert to fraction form
    988.69/1,364.39 = 639.38/x
  3. Step 3: Cross multiply
    988.69x = 1,364.39 × 639.38
  4. Step 4: Simplify right side
    988.69x = 872,363.68
  5. Step 5: Solve for x
    x = 872,363.68/988.69
  6. Step 6: Final answer
    x = 882.34

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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.