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Finding the Fourth Proportional to 815.81, 1,224.45 and 405.81

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Solution

The fourth proportional to 815.81, 1,224.45 and 405.81 is: 609.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.81 : 1,224.45 = 405.81 : x
  2. Step 2: Convert to fraction form
    815.81/1,224.45 = 405.81/x
  3. Step 3: Cross multiply
    815.81x = 1,224.45 × 405.81
  4. Step 4: Simplify right side
    815.81x = 496,894.05
  5. Step 5: Solve for x
    x = 496,894.05/815.81
  6. Step 6: Final answer
    x = 609.08

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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.