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Finding the Fourth Proportional to 1,212.90, 1,672.83 and 770.91

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Solution

The fourth proportional to 1,212.90, 1,672.83 and 770.91 is: 1,063.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.90 : 1,672.83 = 770.91 : x
  2. Step 2: Convert to fraction form
    1,212.90/1,672.83 = 770.91/x
  3. Step 3: Cross multiply
    1,212.90x = 1,672.83 × 770.91
  4. Step 4: Simplify right side
    1,212.90x = 1,289,601.38
  5. Step 5: Solve for x
    x = 1,289,601.38/1,212.90
  6. Step 6: Final answer
    x = 1,063.24

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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.