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Finding the Fourth Proportional to 419.78, 579.20 and 312.03

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Solution

The fourth proportional to 419.78, 579.20 and 312.03 is: 430.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    419.78 : 579.20 = 312.03 : x
  2. Step 2: Convert to fraction form
    419.78/579.20 = 312.03/x
  3. Step 3: Cross multiply
    419.78x = 579.20 × 312.03
  4. Step 4: Simplify right side
    419.78x = 180,726.22
  5. Step 5: Solve for x
    x = 180,726.22/419.78
  6. Step 6: Final answer
    x = 430.52

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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.