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Finding the Fourth Proportional to 815.70, 1,221.50 and 631.56

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Solution

The fourth proportional to 815.70, 1,221.50 and 631.56 is: 945.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.70 : 1,221.50 = 631.56 : x
  2. Step 2: Convert to fraction form
    815.70/1,221.50 = 631.56/x
  3. Step 3: Cross multiply
    815.70x = 1,221.50 × 631.56
  4. Step 4: Simplify right side
    815.70x = 771,450.54
  5. Step 5: Solve for x
    x = 771,450.54/815.70
  6. Step 6: Final answer
    x = 945.75

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.