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Finding the Fourth Proportional to 1,005, 1,387.47 and 783.48

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Solution

The fourth proportional to 1,005, 1,387.47 and 783.48 is: 1,081.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,005 : 1,387.47 = 783.48 : x
  2. Step 2: Convert to fraction form
    1,005/1,387.47 = 783.48/x
  3. Step 3: Cross multiply
    1,005x = 1,387.47 × 783.48
  4. Step 4: Simplify right side
    1,005x = 1,087,055.00
  5. Step 5: Solve for x
    x = 1,087,055.00/1,005
  6. Step 6: Final answer
    x = 1,081.65

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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.