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Finding the Fourth Proportional to 759.12, 1,047.78 and 643.56

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Solution

The fourth proportional to 759.12, 1,047.78 and 643.56 is: 888.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    759.12 : 1,047.78 = 643.56 : x
  2. Step 2: Convert to fraction form
    759.12/1,047.78 = 643.56/x
  3. Step 3: Cross multiply
    759.12x = 1,047.78 × 643.56
  4. Step 4: Simplify right side
    759.12x = 674,309.30
  5. Step 5: Solve for x
    x = 674,309.30/759.12
  6. Step 6: Final answer
    x = 888.28

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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.