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Finding the Fourth Proportional to 839.94, 1,157.62 and 643.72

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Solution

The fourth proportional to 839.94, 1,157.62 and 643.72 is: 887.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.94 : 1,157.62 = 643.72 : x
  2. Step 2: Convert to fraction form
    839.94/1,157.62 = 643.72/x
  3. Step 3: Cross multiply
    839.94x = 1,157.62 × 643.72
  4. Step 4: Simplify right side
    839.94x = 745,183.15
  5. Step 5: Solve for x
    x = 745,183.15/839.94
  6. Step 6: Final answer
    x = 887.19

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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.