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Finding the Fourth Proportional to 485.78, 670.17 and 289.26

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Solution

The fourth proportional to 485.78, 670.17 and 289.26 is: 399.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.78 : 670.17 = 289.26 : x
  2. Step 2: Convert to fraction form
    485.78/670.17 = 289.26/x
  3. Step 3: Cross multiply
    485.78x = 670.17 × 289.26
  4. Step 4: Simplify right side
    485.78x = 193,848.58
  5. Step 5: Solve for x
    x = 193,848.58/485.78
  6. Step 6: Final answer
    x = 399.05

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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.