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Finding the Fourth Proportional to 1,209.65, 1,814.67 and 690.21

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Solution

The fourth proportional to 1,209.65, 1,814.67 and 690.21 is: 1,035.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.65 : 1,814.67 = 690.21 : x
  2. Step 2: Convert to fraction form
    1,209.65/1,814.67 = 690.21/x
  3. Step 3: Cross multiply
    1,209.65x = 1,814.67 × 690.21
  4. Step 4: Simplify right side
    1,209.65x = 1,252,503.38
  5. Step 5: Solve for x
    x = 1,252,503.38/1,209.65
  6. Step 6: Final answer
    x = 1,035.43

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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.