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Finding the Fourth Proportional to 718.78, 1,078.36 and 256.61

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Solution

The fourth proportional to 718.78, 1,078.36 and 256.61 is: 384.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.78 : 1,078.36 = 256.61 : x
  2. Step 2: Convert to fraction form
    718.78/1,078.36 = 256.61/x
  3. Step 3: Cross multiply
    718.78x = 1,078.36 × 256.61
  4. Step 4: Simplify right side
    718.78x = 276,715.39
  5. Step 5: Solve for x
    x = 276,715.39/718.78
  6. Step 6: Final answer
    x = 384.98

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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.