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Finding the Fourth Proportional to 829.21, 1,243.92 and 342.40

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Solution

The fourth proportional to 829.21, 1,243.92 and 342.40 is: 513.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    829.21 : 1,243.92 = 342.40 : x
  2. Step 2: Convert to fraction form
    829.21/1,243.92 = 342.40/x
  3. Step 3: Cross multiply
    829.21x = 1,243.92 × 342.40
  4. Step 4: Simplify right side
    829.21x = 425,918.21
  5. Step 5: Solve for x
    x = 425,918.21/829.21
  6. Step 6: Final answer
    x = 513.64

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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.