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Finding the Fourth Proportional to 805.19, 1,207.58 and 643.59

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Solution

The fourth proportional to 805.19, 1,207.58 and 643.59 is: 965.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.19 : 1,207.58 = 643.59 : x
  2. Step 2: Convert to fraction form
    805.19/1,207.58 = 643.59/x
  3. Step 3: Cross multiply
    805.19x = 1,207.58 × 643.59
  4. Step 4: Simplify right side
    805.19x = 777,183.19
  5. Step 5: Solve for x
    x = 777,183.19/805.19
  6. Step 6: Final answer
    x = 965.22

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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.