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Finding the Fourth Proportional to 397.90, 549.35 and 309.61

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Solution

The fourth proportional to 397.90, 549.35 and 309.61 is: 427.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    397.90 : 549.35 = 309.61 : x
  2. Step 2: Convert to fraction form
    397.90/549.35 = 309.61/x
  3. Step 3: Cross multiply
    397.90x = 549.35 × 309.61
  4. Step 4: Simplify right side
    397.90x = 170,084.25
  5. Step 5: Solve for x
    x = 170,084.25/397.90
  6. Step 6: Final answer
    x = 427.45

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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.