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Finding the Fourth Proportional to 1,138.65, 1,707.98 and 408.21

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Solution

The fourth proportional to 1,138.65, 1,707.98 and 408.21 is: 612.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.65 : 1,707.98 = 408.21 : x
  2. Step 2: Convert to fraction form
    1,138.65/1,707.98 = 408.21/x
  3. Step 3: Cross multiply
    1,138.65x = 1,707.98 × 408.21
  4. Step 4: Simplify right side
    1,138.65x = 697,212.47
  5. Step 5: Solve for x
    x = 697,212.47/1,138.65
  6. Step 6: Final answer
    x = 612.32

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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.