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Finding the Fourth Proportional to 719.21, 1,078.70 and 256.91

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Solution

The fourth proportional to 719.21, 1,078.70 and 256.91 is: 385.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.21 : 1,078.70 = 256.91 : x
  2. Step 2: Convert to fraction form
    719.21/1,078.70 = 256.91/x
  3. Step 3: Cross multiply
    719.21x = 1,078.70 × 256.91
  4. Step 4: Simplify right side
    719.21x = 277,132.16
  5. Step 5: Solve for x
    x = 277,132.16/719.21
  6. Step 6: Final answer
    x = 385.33

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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.