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Finding the Fourth Proportional to 485.67, 670.30 and 308.78

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Solution

The fourth proportional to 485.67, 670.30 and 308.78 is: 426.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.67 : 670.30 = 308.78 : x
  2. Step 2: Convert to fraction form
    485.67/670.30 = 308.78/x
  3. Step 3: Cross multiply
    485.67x = 670.30 × 308.78
  4. Step 4: Simplify right side
    485.67x = 206,971.11
  5. Step 5: Solve for x
    x = 206,971.11/485.67
  6. Step 6: Final answer
    x = 426.16

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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.