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Finding the Fourth Proportional to 486.78, 671.94 and 290.40

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Solution

The fourth proportional to 486.78, 671.94 and 290.40 is: 400.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.78 : 671.94 = 290.40 : x
  2. Step 2: Convert to fraction form
    486.78/671.94 = 290.40/x
  3. Step 3: Cross multiply
    486.78x = 671.94 × 290.40
  4. Step 4: Simplify right side
    486.78x = 195,131.38
  5. Step 5: Solve for x
    x = 195,131.38/486.78
  6. Step 6: Final answer
    x = 400.86

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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.