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Finding the Fourth Proportional to 828.15, 1,143.78 and 643.86

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Solution

The fourth proportional to 828.15, 1,143.78 and 643.86 is: 889.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.15 : 1,143.78 = 643.86 : x
  2. Step 2: Convert to fraction form
    828.15/1,143.78 = 643.86/x
  3. Step 3: Cross multiply
    828.15x = 1,143.78 × 643.86
  4. Step 4: Simplify right side
    828.15x = 736,434.19
  5. Step 5: Solve for x
    x = 736,434.19/828.15
  6. Step 6: Final answer
    x = 889.25

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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.