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Finding the Fourth Proportional to 420.09, 579.87 and 321.72

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Solution

The fourth proportional to 420.09, 579.87 and 321.72 is: 444.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.09 : 579.87 = 321.72 : x
  2. Step 2: Convert to fraction form
    420.09/579.87 = 321.72/x
  3. Step 3: Cross multiply
    420.09x = 579.87 × 321.72
  4. Step 4: Simplify right side
    420.09x = 186,555.78
  5. Step 5: Solve for x
    x = 186,555.78/420.09
  6. Step 6: Final answer
    x = 444.09

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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.