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Finding the Fourth Proportional to 828.21, 1,240.95 and 388.99

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Solution

The fourth proportional to 828.21, 1,240.95 and 388.99 is: 582.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.21 : 1,240.95 = 388.99 : x
  2. Step 2: Convert to fraction form
    828.21/1,240.95 = 388.99/x
  3. Step 3: Cross multiply
    828.21x = 1,240.95 × 388.99
  4. Step 4: Simplify right side
    828.21x = 482,717.14
  5. Step 5: Solve for x
    x = 482,717.14/828.21
  6. Step 6: Final answer
    x = 582.85

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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.