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Finding the Fourth Proportional to 393.80, 542.79 and 310.77

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Solution

The fourth proportional to 393.80, 542.79 and 310.77 is: 428.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.80 : 542.79 = 310.77 : x
  2. Step 2: Convert to fraction form
    393.80/542.79 = 310.77/x
  3. Step 3: Cross multiply
    393.80x = 542.79 × 310.77
  4. Step 4: Simplify right side
    393.80x = 168,682.85
  5. Step 5: Solve for x
    x = 168,682.85/393.80
  6. Step 6: Final answer
    x = 428.35

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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.