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Finding the Fourth Proportional to 919.74, 1,378.89 and 486.66

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Solution

The fourth proportional to 919.74, 1,378.89 and 486.66 is: 729.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.74 : 1,378.89 = 486.66 : x
  2. Step 2: Convert to fraction form
    919.74/1,378.89 = 486.66/x
  3. Step 3: Cross multiply
    919.74x = 1,378.89 × 486.66
  4. Step 4: Simplify right side
    919.74x = 671,050.61
  5. Step 5: Solve for x
    x = 671,050.61/919.74
  6. Step 6: Final answer
    x = 729.61

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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.