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Finding the Fourth Proportional to 393.90, 542.69 and 310.98

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Solution

The fourth proportional to 393.90, 542.69 and 310.98 is: 428.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.90 : 542.69 = 310.98 : x
  2. Step 2: Convert to fraction form
    393.90/542.69 = 310.98/x
  3. Step 3: Cross multiply
    393.90x = 542.69 × 310.98
  4. Step 4: Simplify right side
    393.90x = 168,765.74
  5. Step 5: Solve for x
    x = 168,765.74/393.90
  6. Step 6: Final answer
    x = 428.45

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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.