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Finding the Fourth Proportional to 800.40, 1,200.50 and 313.80

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Solution

The fourth proportional to 800.40, 1,200.50 and 313.80 is: 470.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    800.40 : 1,200.50 = 313.80 : x
  2. Step 2: Convert to fraction form
    800.40/1,200.50 = 313.80/x
  3. Step 3: Cross multiply
    800.40x = 1,200.50 × 313.80
  4. Step 4: Simplify right side
    800.40x = 376,716.90
  5. Step 5: Solve for x
    x = 376,716.90/800.40
  6. Step 6: Final answer
    x = 470.66

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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.