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Finding the Fourth Proportional to 826.21, 1,239.38 and 278.40

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Solution

The fourth proportional to 826.21, 1,239.38 and 278.40 is: 417.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    826.21 : 1,239.38 = 278.40 : x
  2. Step 2: Convert to fraction form
    826.21/1,239.38 = 278.40/x
  3. Step 3: Cross multiply
    826.21x = 1,239.38 × 278.40
  4. Step 4: Simplify right side
    826.21x = 345,043.39
  5. Step 5: Solve for x
    x = 345,043.39/826.21
  6. Step 6: Final answer
    x = 417.62

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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.