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Finding the Fourth Proportional to 857.71, 1,286.56 and 208.45

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Solution

The fourth proportional to 857.71, 1,286.56 and 208.45 is: 312.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.71 : 1,286.56 = 208.45 : x
  2. Step 2: Convert to fraction form
    857.71/1,286.56 = 208.45/x
  3. Step 3: Cross multiply
    857.71x = 1,286.56 × 208.45
  4. Step 4: Simplify right side
    857.71x = 268,176.48
  5. Step 5: Solve for x
    x = 268,176.48/857.71
  6. Step 6: Final answer
    x = 312.66

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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.