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Finding the Fourth Proportional to 657.90, 986.89 and 213.21

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Solution

The fourth proportional to 657.90, 986.89 and 213.21 is: 319.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    657.90 : 986.89 = 213.21 : x
  2. Step 2: Convert to fraction form
    657.90/986.89 = 213.21/x
  3. Step 3: Cross multiply
    657.90x = 986.89 × 213.21
  4. Step 4: Simplify right side
    657.90x = 210,408.82
  5. Step 5: Solve for x
    x = 210,408.82/657.90
  6. Step 6: Final answer
    x = 319.82

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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.