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Finding the Fourth Proportional to 485.20, 669.72 and 386.92

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Solution

The fourth proportional to 485.20, 669.72 and 386.92 is: 534.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.20 : 669.72 = 386.92 : x
  2. Step 2: Convert to fraction form
    485.20/669.72 = 386.92/x
  3. Step 3: Cross multiply
    485.20x = 669.72 × 386.92
  4. Step 4: Simplify right side
    485.20x = 259,128.06
  5. Step 5: Solve for x
    x = 259,128.06/485.20
  6. Step 6: Final answer
    x = 534.06

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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.