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Finding the Fourth Proportional to 857.28, 1,286.88 and 424.32

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Solution

The fourth proportional to 857.28, 1,286.88 and 424.32 is: 636.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.28 : 1,286.88 = 424.32 : x
  2. Step 2: Convert to fraction form
    857.28/1,286.88 = 424.32/x
  3. Step 3: Cross multiply
    857.28x = 1,286.88 × 424.32
  4. Step 4: Simplify right side
    857.28x = 546,048.92
  5. Step 5: Solve for x
    x = 546,048.92/857.28
  6. Step 6: Final answer
    x = 636.96

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.