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Finding the Fourth Proportional to 1,212, 1,672.56 and 688.11

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Solution

The fourth proportional to 1,212, 1,672.56 and 688.11 is: 949.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212 : 1,672.56 = 688.11 : x
  2. Step 2: Convert to fraction form
    1,212/1,672.56 = 688.11/x
  3. Step 3: Cross multiply
    1,212x = 1,672.56 × 688.11
  4. Step 4: Simplify right side
    1,212x = 1,150,905.26
  5. Step 5: Solve for x
    x = 1,150,905.26/1,212
  6. Step 6: Final answer
    x = 949.59

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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.