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Finding the Fourth Proportional to 420.30, 579.69 and 315.42

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Solution

The fourth proportional to 420.30, 579.69 and 315.42 is: 435.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.30 : 579.69 = 315.42 : x
  2. Step 2: Convert to fraction form
    420.30/579.69 = 315.42/x
  3. Step 3: Cross multiply
    420.30x = 579.69 × 315.42
  4. Step 4: Simplify right side
    420.30x = 182,845.82
  5. Step 5: Solve for x
    x = 182,845.82/420.30
  6. Step 6: Final answer
    x = 435.04

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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.