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Finding the Fourth Proportional to 920.40, 1,379.78 and 342.88

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Solution

The fourth proportional to 920.40, 1,379.78 and 342.88 is: 514.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.40 : 1,379.78 = 342.88 : x
  2. Step 2: Convert to fraction form
    920.40/1,379.78 = 342.88/x
  3. Step 3: Cross multiply
    920.40x = 1,379.78 × 342.88
  4. Step 4: Simplify right side
    920.40x = 473,098.97
  5. Step 5: Solve for x
    x = 473,098.97/920.40
  6. Step 6: Final answer
    x = 514.01

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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.