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Finding the Fourth Proportional to 858.59, 1,287.87 and 209.32

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Solution

The fourth proportional to 858.59, 1,287.87 and 209.32 is: 313.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.59 : 1,287.87 = 209.32 : x
  2. Step 2: Convert to fraction form
    858.59/1,287.87 = 209.32/x
  3. Step 3: Cross multiply
    858.59x = 1,287.87 × 209.32
  4. Step 4: Simplify right side
    858.59x = 269,576.95
  5. Step 5: Solve for x
    x = 269,576.95/858.59
  6. Step 6: Final answer
    x = 313.98

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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.