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Finding the Fourth Proportional to 643.55, 888.26 and 420.04

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Solution

The fourth proportional to 643.55, 888.26 and 420.04 is: 579.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.55 : 888.26 = 420.04 : x
  2. Step 2: Convert to fraction form
    643.55/888.26 = 420.04/x
  3. Step 3: Cross multiply
    643.55x = 888.26 × 420.04
  4. Step 4: Simplify right side
    643.55x = 373,104.73
  5. Step 5: Solve for x
    x = 373,104.73/643.55
  6. Step 6: Final answer
    x = 579.76

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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.