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Finding the Fourth Proportional to 812.48, 1,120.80 and 480.80

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Solution

The fourth proportional to 812.48, 1,120.80 and 480.80 is: 663.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.48 : 1,120.80 = 480.80 : x
  2. Step 2: Convert to fraction form
    812.48/1,120.80 = 480.80/x
  3. Step 3: Cross multiply
    812.48x = 1,120.80 × 480.80
  4. Step 4: Simplify right side
    812.48x = 538,880.64
  5. Step 5: Solve for x
    x = 538,880.64/812.48
  6. Step 6: Final answer
    x = 663.25

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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.