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Finding the Fourth Proportional to 827.21, 1,240.78 and 279.39

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Solution

The fourth proportional to 827.21, 1,240.78 and 279.39 is: 419.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    827.21 : 1,240.78 = 279.39 : x
  2. Step 2: Convert to fraction form
    827.21/1,240.78 = 279.39/x
  3. Step 3: Cross multiply
    827.21x = 1,240.78 × 279.39
  4. Step 4: Simplify right side
    827.21x = 346,661.52
  5. Step 5: Solve for x
    x = 346,661.52/827.21
  6. Step 6: Final answer
    x = 419.07

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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.