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Finding the Fourth Proportional to 820.20, 1,131.60 and 645.24

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Solution

The fourth proportional to 820.20, 1,131.60 and 645.24 is: 890.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.20 : 1,131.60 = 645.24 : x
  2. Step 2: Convert to fraction form
    820.20/1,131.60 = 645.24/x
  3. Step 3: Cross multiply
    820.20x = 1,131.60 × 645.24
  4. Step 4: Simplify right side
    820.20x = 730,153.58
  5. Step 5: Solve for x
    x = 730,153.58/820.20
  6. Step 6: Final answer
    x = 890.21

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1.5x scale

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.