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Finding the Fourth Proportional to 485.97, 670.19 and 420.09

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Solution

The fourth proportional to 485.97, 670.19 and 420.09 is: 579.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.97 : 670.19 = 420.09 : x
  2. Step 2: Convert to fraction form
    485.97/670.19 = 420.09/x
  3. Step 3: Cross multiply
    485.97x = 670.19 × 420.09
  4. Step 4: Simplify right side
    485.97x = 281,538.02
  5. Step 5: Solve for x
    x = 281,538.02/485.97
  6. Step 6: Final answer
    x = 579.33

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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.