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Finding the Fourth Proportional to 858.74, 1,288.11 and 209.47

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Solution

The fourth proportional to 858.74, 1,288.11 and 209.47 is: 314.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.74 : 1,288.11 = 209.47 : x
  2. Step 2: Convert to fraction form
    858.74/1,288.11 = 209.47/x
  3. Step 3: Cross multiply
    858.74x = 1,288.11 × 209.47
  4. Step 4: Simplify right side
    858.74x = 269,820.40
  5. Step 5: Solve for x
    x = 269,820.40/858.74
  6. Step 6: Final answer
    x = 314.21

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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.