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Finding the Fourth Proportional to 1,139.68, 1,573.38 and 787.60

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Solution

The fourth proportional to 1,139.68, 1,573.38 and 787.60 is: 1,087.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.68 : 1,573.38 = 787.60 : x
  2. Step 2: Convert to fraction form
    1,139.68/1,573.38 = 787.60/x
  3. Step 3: Cross multiply
    1,139.68x = 1,573.38 × 787.60
  4. Step 4: Simplify right side
    1,139.68x = 1,239,194.09
  5. Step 5: Solve for x
    x = 1,239,194.09/1,139.68
  6. Step 6: Final answer
    x = 1,087.32

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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.