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Finding the Fourth Proportional to 1,381.44, 1,903.76 and 987.78

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Solution

The fourth proportional to 1,381.44, 1,903.76 and 987.78 is: 1,361.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,381.44 : 1,903.76 = 987.78 : x
  2. Step 2: Convert to fraction form
    1,381.44/1,903.76 = 987.78/x
  3. Step 3: Cross multiply
    1,381.44x = 1,903.76 × 987.78
  4. Step 4: Simplify right side
    1,381.44x = 1,880,496.05
  5. Step 5: Solve for x
    x = 1,880,496.05/1,381.44
  6. Step 6: Final answer
    x = 1,361.26

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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.