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Finding the Fourth Proportional to 919.20, 1,379.40 and 486.68

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Solution

The fourth proportional to 919.20, 1,379.40 and 486.68 is: 730.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.20 : 1,379.40 = 486.68 : x
  2. Step 2: Convert to fraction form
    919.20/1,379.40 = 486.68/x
  3. Step 3: Cross multiply
    919.20x = 1,379.40 × 486.68
  4. Step 4: Simplify right side
    919.20x = 671,326.39
  5. Step 5: Solve for x
    x = 671,326.39/919.20
  6. Step 6: Final answer
    x = 730.34

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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.