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Finding the Fourth Proportional to 828.36, 1,145.88 and 643.68

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Solution

The fourth proportional to 828.36, 1,145.88 and 643.68 is: 890.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.36 : 1,145.88 = 643.68 : x
  2. Step 2: Convert to fraction form
    828.36/1,145.88 = 643.68/x
  3. Step 3: Cross multiply
    828.36x = 1,145.88 × 643.68
  4. Step 4: Simplify right side
    828.36x = 737,580.04
  5. Step 5: Solve for x
    x = 737,580.04/828.36
  6. Step 6: Final answer
    x = 890.41

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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.