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Finding the Fourth Proportional to 919.68, 1,379.28 and 486.64

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Solution

The fourth proportional to 919.68, 1,379.28 and 486.64 is: 729.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.68 : 1,379.28 = 486.64 : x
  2. Step 2: Convert to fraction form
    919.68/1,379.28 = 486.64/x
  3. Step 3: Cross multiply
    919.68x = 1,379.28 × 486.64
  4. Step 4: Simplify right side
    919.68x = 671,212.82
  5. Step 5: Solve for x
    x = 671,212.82/919.68
  6. Step 6: Final answer
    x = 729.83

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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.