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Finding the Fourth Proportional to 1,209.22, 1,668.87 and 685.15

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Solution

The fourth proportional to 1,209.22, 1,668.87 and 685.15 is: 945.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.22 : 1,668.87 = 685.15 : x
  2. Step 2: Convert to fraction form
    1,209.22/1,668.87 = 685.15/x
  3. Step 3: Cross multiply
    1,209.22x = 1,668.87 × 685.15
  4. Step 4: Simplify right side
    1,209.22x = 1,143,417.94
  5. Step 5: Solve for x
    x = 1,143,417.94/1,209.22
  6. Step 6: Final answer
    x = 945.59

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.