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Finding the Fourth Proportional to 642.74, 887.06 and 394.09

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Solution

The fourth proportional to 642.74, 887.06 and 394.09 is: 543.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.74 : 887.06 = 394.09 : x
  2. Step 2: Convert to fraction form
    642.74/887.06 = 394.09/x
  3. Step 3: Cross multiply
    642.74x = 887.06 × 394.09
  4. Step 4: Simplify right side
    642.74x = 349,579.50
  5. Step 5: Solve for x
    x = 349,579.50/642.74
  6. Step 6: Final answer
    x = 543.89

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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.