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Finding the Fourth Proportional to 420.11, 579.12 and 279.98

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Solution

The fourth proportional to 420.11, 579.12 and 279.98 is: 385.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.11 : 579.12 = 279.98 : x
  2. Step 2: Convert to fraction form
    420.11/579.12 = 279.98/x
  3. Step 3: Cross multiply
    420.11x = 579.12 × 279.98
  4. Step 4: Simplify right side
    420.11x = 162,142.02
  5. Step 5: Solve for x
    x = 162,142.02/420.11
  6. Step 6: Final answer
    x = 385.95

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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.