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Finding the Fourth Proportional to 310.28, 428.10 and 287

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Solution

The fourth proportional to 310.28, 428.10 and 287 is: 395.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.28 : 428.10 = 287 : x
  2. Step 2: Convert to fraction form
    310.28/428.10 = 287/x
  3. Step 3: Cross multiply
    310.28x = 428.10 × 287
  4. Step 4: Simplify right side
    310.28x = 122,864.70
  5. Step 5: Solve for x
    x = 122,864.70/310.28
  6. Step 6: Final answer
    x = 395.98

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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.