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Finding the Fourth Proportional to 685.72, 1,029.20 and 612.48

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Solution

The fourth proportional to 685.72, 1,029.20 and 612.48 is: 919.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.72 : 1,029.20 = 612.48 : x
  2. Step 2: Convert to fraction form
    685.72/1,029.20 = 612.48/x
  3. Step 3: Cross multiply
    685.72x = 1,029.20 × 612.48
  4. Step 4: Simplify right side
    685.72x = 630,364.42
  5. Step 5: Solve for x
    x = 630,364.42/685.72
  6. Step 6: Final answer
    x = 919.27

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.