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Finding the Fourth Proportional to 815.78, 1,223.07 and 491.07

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Solution

The fourth proportional to 815.78, 1,223.07 and 491.07 is: 736.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.78 : 1,223.07 = 491.07 : x
  2. Step 2: Convert to fraction form
    815.78/1,223.07 = 491.07/x
  3. Step 3: Cross multiply
    815.78x = 1,223.07 × 491.07
  4. Step 4: Simplify right side
    815.78x = 600,615.73
  5. Step 5: Solve for x
    x = 600,615.73/815.78
  6. Step 6: Final answer
    x = 736.24

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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.