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Finding the Fourth Proportional to 820.64, 1,132.56 and 645.60

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Solution

The fourth proportional to 820.64, 1,132.56 and 645.60 is: 890.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.64 : 1,132.56 = 645.60 : x
  2. Step 2: Convert to fraction form
    820.64/1,132.56 = 645.60/x
  3. Step 3: Cross multiply
    820.64x = 1,132.56 × 645.60
  4. Step 4: Simplify right side
    820.64x = 731,180.74
  5. Step 5: Solve for x
    x = 731,180.74/820.64
  6. Step 6: Final answer
    x = 890.99

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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.