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Finding the Fourth Proportional to 486.95, 671.92 and 287.78

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Solution

The fourth proportional to 486.95, 671.92 and 287.78 is: 397.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.95 : 671.92 = 287.78 : x
  2. Step 2: Convert to fraction form
    486.95/671.92 = 287.78/x
  3. Step 3: Cross multiply
    486.95x = 671.92 × 287.78
  4. Step 4: Simplify right side
    486.95x = 193,361.06
  5. Step 5: Solve for x
    x = 193,361.06/486.95
  6. Step 6: Final answer
    x = 397.09

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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.