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Finding the Fourth Proportional to 805.76, 1,209.09 and 690.94

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Solution

The fourth proportional to 805.76, 1,209.09 and 690.94 is: 1,036.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.76 : 1,209.09 = 690.94 : x
  2. Step 2: Convert to fraction form
    805.76/1,209.09 = 690.94/x
  3. Step 3: Cross multiply
    805.76x = 1,209.09 × 690.94
  4. Step 4: Simplify right side
    805.76x = 835,412.75
  5. Step 5: Solve for x
    x = 835,412.75/805.76
  6. Step 6: Final answer
    x = 1,036.80

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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.