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Finding the Fourth Proportional to 812.40, 1,118.48 and 687.72

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Solution

The fourth proportional to 812.40, 1,118.48 and 687.72 is: 946.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.40 : 1,118.48 = 687.72 : x
  2. Step 2: Convert to fraction form
    812.40/1,118.48 = 687.72/x
  3. Step 3: Cross multiply
    812.40x = 1,118.48 × 687.72
  4. Step 4: Simplify right side
    812.40x = 769,201.07
  5. Step 5: Solve for x
    x = 769,201.07/812.40
  6. Step 6: Final answer
    x = 946.83

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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.