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Finding the Fourth Proportional to 857.79, 1,286.58 and 272.78

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Solution

The fourth proportional to 857.79, 1,286.58 and 272.78 is: 409.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.79 : 1,286.58 = 272.78 : x
  2. Step 2: Convert to fraction form
    857.79/1,286.58 = 272.78/x
  3. Step 3: Cross multiply
    857.79x = 1,286.58 × 272.78
  4. Step 4: Simplify right side
    857.79x = 350,946.86
  5. Step 5: Solve for x
    x = 350,946.86/857.79
  6. Step 6: Final answer
    x = 409.13

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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.