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Finding the Fourth Proportional to 1,209.12, 1,668.59 and 685.14

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Solution

The fourth proportional to 1,209.12, 1,668.59 and 685.14 is: 945.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.12 : 1,668.59 = 685.14 : x
  2. Step 2: Convert to fraction form
    1,209.12/1,668.59 = 685.14/x
  3. Step 3: Cross multiply
    1,209.12x = 1,668.59 × 685.14
  4. Step 4: Simplify right side
    1,209.12x = 1,143,217.75
  5. Step 5: Solve for x
    x = 1,143,217.75/1,209.12
  6. Step 6: Final answer
    x = 945.50

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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.