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Finding the Fourth Proportional to 969.20, 1,334.40 and 821.60

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Solution

The fourth proportional to 969.20, 1,334.40 and 821.60 is: 1,131.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    969.20 : 1,334.40 = 821.60 : x
  2. Step 2: Convert to fraction form
    969.20/1,334.40 = 821.60/x
  3. Step 3: Cross multiply
    969.20x = 1,334.40 × 821.60
  4. Step 4: Simplify right side
    969.20x = 1,096,343.04
  5. Step 5: Solve for x
    x = 1,096,343.04/969.20
  6. Step 6: Final answer
    x = 1,131.18

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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.