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Finding the Fourth Proportional to 987.21, 1,361.19 and 672.66

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Solution

The fourth proportional to 987.21, 1,361.19 and 672.66 is: 927.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.21 : 1,361.19 = 672.66 : x
  2. Step 2: Convert to fraction form
    987.21/1,361.19 = 672.66/x
  3. Step 3: Cross multiply
    987.21x = 1,361.19 × 672.66
  4. Step 4: Simplify right side
    987.21x = 915,620.59
  5. Step 5: Solve for x
    x = 915,620.59/987.21
  6. Step 6: Final answer
    x = 927.48

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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.