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Finding the Fourth Proportional to 800.65, 1,200.75 and 388.99

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Solution

The fourth proportional to 800.65, 1,200.75 and 388.99 is: 583.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    800.65 : 1,200.75 = 388.99 : x
  2. Step 2: Convert to fraction form
    800.65/1,200.75 = 388.99/x
  3. Step 3: Cross multiply
    800.65x = 1,200.75 × 388.99
  4. Step 4: Simplify right side
    800.65x = 467,079.74
  5. Step 5: Solve for x
    x = 467,079.74/800.65
  6. Step 6: Final answer
    x = 583.38

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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.