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Finding the Fourth Proportional to 821.16, 1,236.62 and 748.80

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Solution

The fourth proportional to 821.16, 1,236.62 and 748.80 is: 1,127.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.16 : 1,236.62 = 748.80 : x
  2. Step 2: Convert to fraction form
    821.16/1,236.62 = 748.80/x
  3. Step 3: Cross multiply
    821.16x = 1,236.62 × 748.80
  4. Step 4: Simplify right side
    821.16x = 925,981.06
  5. Step 5: Solve for x
    x = 925,981.06/821.16
  6. Step 6: Final answer
    x = 1,127.65

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.