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Finding the Fourth Proportional to 1,209.29, 1,668.67 and 678.20

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Solution

The fourth proportional to 1,209.29, 1,668.67 and 678.20 is: 935.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.29 : 1,668.67 = 678.20 : x
  2. Step 2: Convert to fraction form
    1,209.29/1,668.67 = 678.20/x
  3. Step 3: Cross multiply
    1,209.29x = 1,668.67 × 678.20
  4. Step 4: Simplify right side
    1,209.29x = 1,131,691.99
  5. Step 5: Solve for x
    x = 1,131,691.99/1,209.29
  6. Step 6: Final answer
    x = 935.83

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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.