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Finding the Fourth Proportional to 678.72, 1,017.72 and 239.76

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Solution

The fourth proportional to 678.72, 1,017.72 and 239.76 is: 359.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.72 : 1,017.72 = 239.76 : x
  2. Step 2: Convert to fraction form
    678.72/1,017.72 = 239.76/x
  3. Step 3: Cross multiply
    678.72x = 1,017.72 × 239.76
  4. Step 4: Simplify right side
    678.72x = 244,008.55
  5. Step 5: Solve for x
    x = 244,008.55/678.72
  6. Step 6: Final answer
    x = 359.51

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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.