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Finding the Fourth Proportional to 485.72, 670.20 and 289.16

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Solution

The fourth proportional to 485.72, 670.20 and 289.16 is: 398.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.72 : 670.20 = 289.16 : x
  2. Step 2: Convert to fraction form
    485.72/670.20 = 289.16/x
  3. Step 3: Cross multiply
    485.72x = 670.20 × 289.16
  4. Step 4: Simplify right side
    485.72x = 193,795.03
  5. Step 5: Solve for x
    x = 193,795.03/485.72
  6. Step 6: Final answer
    x = 398.99

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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.