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Finding the Fourth Proportional to 919.01, 1,378.01 and 391.79

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Solution

The fourth proportional to 919.01, 1,378.01 and 391.79 is: 587.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.01 : 1,378.01 = 391.79 : x
  2. Step 2: Convert to fraction form
    919.01/1,378.01 = 391.79/x
  3. Step 3: Cross multiply
    919.01x = 1,378.01 × 391.79
  4. Step 4: Simplify right side
    919.01x = 539,894.96
  5. Step 5: Solve for x
    x = 539,894.96/919.01
  6. Step 6: Final answer
    x = 587.47

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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.