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Finding the Fourth Proportional to 919.70, 1,379.55 and 406.70

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Solution

The fourth proportional to 919.70, 1,379.55 and 406.70 is: 610.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.70 : 1,379.55 = 406.70 : x
  2. Step 2: Convert to fraction form
    919.70/1,379.55 = 406.70/x
  3. Step 3: Cross multiply
    919.70x = 1,379.55 × 406.70
  4. Step 4: Simplify right side
    919.70x = 561,062.99
  5. Step 5: Solve for x
    x = 561,062.99/919.70
  6. Step 6: Final answer
    x = 610.05

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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.