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Finding the Fourth Proportional to 485.76, 670.08 and 289.20

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Solution

The fourth proportional to 485.76, 670.08 and 289.20 is: 398.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.76 : 670.08 = 289.20 : x
  2. Step 2: Convert to fraction form
    485.76/670.08 = 289.20/x
  3. Step 3: Cross multiply
    485.76x = 670.08 × 289.20
  4. Step 4: Simplify right side
    485.76x = 193,787.14
  5. Step 5: Solve for x
    x = 193,787.14/485.76
  6. Step 6: Final answer
    x = 398.94

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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.