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Finding the Fourth Proportional to 420.09, 579.74 and 315.20

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Solution

The fourth proportional to 420.09, 579.74 and 315.20 is: 434.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.09 : 579.74 = 315.20 : x
  2. Step 2: Convert to fraction form
    420.09/579.74 = 315.20/x
  3. Step 3: Cross multiply
    420.09x = 579.74 × 315.20
  4. Step 4: Simplify right side
    420.09x = 182,729.57
  5. Step 5: Solve for x
    x = 182,729.57/420.09
  6. Step 6: Final answer
    x = 434.98

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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.