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Finding the Fourth Proportional to 421.11, 579.78 and 347.30

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Solution

The fourth proportional to 421.11, 579.78 and 347.30 is: 478.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.11 : 579.78 = 347.30 : x
  2. Step 2: Convert to fraction form
    421.11/579.78 = 347.30/x
  3. Step 3: Cross multiply
    421.11x = 579.78 × 347.30
  4. Step 4: Simplify right side
    421.11x = 201,357.59
  5. Step 5: Solve for x
    x = 201,357.59/421.11
  6. Step 6: Final answer
    x = 478.16

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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.