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Finding the Fourth Proportional to 1,081.45, 1,621.32 and 388

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Solution

The fourth proportional to 1,081.45, 1,621.32 and 388 is: 581.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,081.45 : 1,621.32 = 388 : x
  2. Step 2: Convert to fraction form
    1,081.45/1,621.32 = 388/x
  3. Step 3: Cross multiply
    1,081.45x = 1,621.32 × 388
  4. Step 4: Simplify right side
    1,081.45x = 629,072.16
  5. Step 5: Solve for x
    x = 629,072.16/1,081.45
  6. Step 6: Final answer
    x = 581.69

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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.