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Finding the Fourth Proportional to 718.59, 1,078.40 and 256.40

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Solution

The fourth proportional to 718.59, 1,078.40 and 256.40 is: 384.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.59 : 1,078.40 = 256.40 : x
  2. Step 2: Convert to fraction form
    718.59/1,078.40 = 256.40/x
  3. Step 3: Cross multiply
    718.59x = 1,078.40 × 256.40
  4. Step 4: Simplify right side
    718.59x = 276,501.76
  5. Step 5: Solve for x
    x = 276,501.76/718.59
  6. Step 6: Final answer
    x = 384.78

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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.