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Finding the Fourth Proportional to 919.72, 1,378.65 and 456.79

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Solution

The fourth proportional to 919.72, 1,378.65 and 456.79 is: 684.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.72 : 1,378.65 = 456.79 : x
  2. Step 2: Convert to fraction form
    919.72/1,378.65 = 456.79/x
  3. Step 3: Cross multiply
    919.72x = 1,378.65 × 456.79
  4. Step 4: Simplify right side
    919.72x = 629,753.53
  5. Step 5: Solve for x
    x = 629,753.53/919.72
  6. Step 6: Final answer
    x = 684.72

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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.