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Finding the Fourth Proportional to 919.32, 1,379.20 and 486.38

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Solution

The fourth proportional to 919.32, 1,379.20 and 486.38 is: 729.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.32 : 1,379.20 = 486.38 : x
  2. Step 2: Convert to fraction form
    919.32/1,379.20 = 486.38/x
  3. Step 3: Cross multiply
    919.32x = 1,379.20 × 486.38
  4. Step 4: Simplify right side
    919.32x = 670,815.30
  5. Step 5: Solve for x
    x = 670,815.30/919.32
  6. Step 6: Final answer
    x = 729.69

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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.