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Finding the Fourth Proportional to 858.66, 1,287.98 and 209.39

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Solution

The fourth proportional to 858.66, 1,287.98 and 209.39 is: 314.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.66 : 1,287.98 = 209.39 : x
  2. Step 2: Convert to fraction form
    858.66/1,287.98 = 209.39/x
  3. Step 3: Cross multiply
    858.66x = 1,287.98 × 209.39
  4. Step 4: Simplify right side
    858.66x = 269,690.13
  5. Step 5: Solve for x
    x = 269,690.13/858.66
  6. Step 6: Final answer
    x = 314.08

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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.