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Finding the Fourth Proportional to 1,142.87, 1,577.13 and 645.45

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Solution

The fourth proportional to 1,142.87, 1,577.13 and 645.45 is: 890.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,142.87 : 1,577.13 = 645.45 : x
  2. Step 2: Convert to fraction form
    1,142.87/1,577.13 = 645.45/x
  3. Step 3: Cross multiply
    1,142.87x = 1,577.13 × 645.45
  4. Step 4: Simplify right side
    1,142.87x = 1,017,958.56
  5. Step 5: Solve for x
    x = 1,017,958.56/1,142.87
  6. Step 6: Final answer
    x = 890.71

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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.