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Finding the Fourth Proportional to 815.40, 1,222.94 and 419.88

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Solution

The fourth proportional to 815.40, 1,222.94 and 419.88 is: 629.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.40 : 1,222.94 = 419.88 : x
  2. Step 2: Convert to fraction form
    815.40/1,222.94 = 419.88/x
  3. Step 3: Cross multiply
    815.40x = 1,222.94 × 419.88
  4. Step 4: Simplify right side
    815.40x = 513,488.05
  5. Step 5: Solve for x
    x = 513,488.05/815.40
  6. Step 6: Final answer
    x = 629.74

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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.