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Finding the Fourth Proportional to 642.04, 885.36 and 420.76

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Solution

The fourth proportional to 642.04, 885.36 and 420.76 is: 580.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.04 : 885.36 = 420.76 : x
  2. Step 2: Convert to fraction form
    642.04/885.36 = 420.76/x
  3. Step 3: Cross multiply
    642.04x = 885.36 × 420.76
  4. Step 4: Simplify right side
    642.04x = 372,524.07
  5. Step 5: Solve for x
    x = 372,524.07/642.04
  6. Step 6: Final answer
    x = 580.22

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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.