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Finding the Fourth Proportional to 812.61, 1,121.05 and 480.90

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Solution

The fourth proportional to 812.61, 1,121.05 and 480.90 is: 663.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.61 : 1,121.05 = 480.90 : x
  2. Step 2: Convert to fraction form
    812.61/1,121.05 = 480.90/x
  3. Step 3: Cross multiply
    812.61x = 1,121.05 × 480.90
  4. Step 4: Simplify right side
    812.61x = 539,112.95
  5. Step 5: Solve for x
    x = 539,112.95/812.61
  6. Step 6: Final answer
    x = 663.43

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Double scale
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1.5x scale

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.