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Finding the Fourth Proportional to 642.79, 887.07 and 394.05

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Solution

The fourth proportional to 642.79, 887.07 and 394.05 is: 543.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.79 : 887.07 = 394.05 : x
  2. Step 2: Convert to fraction form
    642.79/887.07 = 394.05/x
  3. Step 3: Cross multiply
    642.79x = 887.07 × 394.05
  4. Step 4: Simplify right side
    642.79x = 349,549.93
  5. Step 5: Solve for x
    x = 349,549.93/642.79
  6. Step 6: Final answer
    x = 543.80

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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.