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Finding the Fourth Proportional to 310.80, 428.76 and 285.84

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Solution

The fourth proportional to 310.80, 428.76 and 285.84 is: 394.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.80 : 428.76 = 285.84 : x
  2. Step 2: Convert to fraction form
    310.80/428.76 = 285.84/x
  3. Step 3: Cross multiply
    310.80x = 428.76 × 285.84
  4. Step 4: Simplify right side
    310.80x = 122,556.76
  5. Step 5: Solve for x
    x = 122,556.76/310.80
  6. Step 6: Final answer
    x = 394.33

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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.