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Finding the Fourth Proportional to 862.48, 1,285.01 and 821.20

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Solution

The fourth proportional to 862.48, 1,285.01 and 821.20 is: 1,223.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    862.48 : 1,285.01 = 821.20 : x
  2. Step 2: Convert to fraction form
    862.48/1,285.01 = 821.20/x
  3. Step 3: Cross multiply
    862.48x = 1,285.01 × 821.20
  4. Step 4: Simplify right side
    862.48x = 1,055,250.21
  5. Step 5: Solve for x
    x = 1,055,250.21/862.48
  6. Step 6: Final answer
    x = 1,223.51

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.