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Finding the Fourth Proportional to 665.61, 998.42 and 647.39

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Solution

The fourth proportional to 665.61, 998.42 and 647.39 is: 971.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.61 : 998.42 = 647.39 : x
  2. Step 2: Convert to fraction form
    665.61/998.42 = 647.39/x
  3. Step 3: Cross multiply
    665.61x = 998.42 × 647.39
  4. Step 4: Simplify right side
    665.61x = 646,358.89
  5. Step 5: Solve for x
    x = 646,358.89/665.61
  6. Step 6: Final answer
    x = 971.08

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.