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Finding the Fourth Proportional to 678.79, 1,018.31 and 256.63

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Solution

The fourth proportional to 678.79, 1,018.31 and 256.63 is: 384.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.79 : 1,018.31 = 256.63 : x
  2. Step 2: Convert to fraction form
    678.79/1,018.31 = 256.63/x
  3. Step 3: Cross multiply
    678.79x = 1,018.31 × 256.63
  4. Step 4: Simplify right side
    678.79x = 261,327.61
  5. Step 5: Solve for x
    x = 261,327.61/678.79
  6. Step 6: Final answer
    x = 384.99

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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.