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Finding the Fourth Proportional to 1,320.45, 1,821.15 and 822.15

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Solution

The fourth proportional to 1,320.45, 1,821.15 and 822.15 is: 1,133.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,320.45 : 1,821.15 = 822.15 : x
  2. Step 2: Convert to fraction form
    1,320.45/1,821.15 = 822.15/x
  3. Step 3: Cross multiply
    1,320.45x = 1,821.15 × 822.15
  4. Step 4: Simplify right side
    1,320.45x = 1,497,258.47
  5. Step 5: Solve for x
    x = 1,497,258.47/1,320.45
  6. Step 6: Final answer
    x = 1,133.90

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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.