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Finding the Fourth Proportional to 815.86, 1,223.79 and 328.78

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Solution

The fourth proportional to 815.86, 1,223.79 and 328.78 is: 493.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.86 : 1,223.79 = 328.78 : x
  2. Step 2: Convert to fraction form
    815.86/1,223.79 = 328.78/x
  3. Step 3: Cross multiply
    815.86x = 1,223.79 × 328.78
  4. Step 4: Simplify right side
    815.86x = 402,357.68
  5. Step 5: Solve for x
    x = 402,357.68/815.86
  6. Step 6: Final answer
    x = 493.17

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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.