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Finding the Fourth Proportional to 1,003.51, 1,387.52 and 987.85

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Solution

The fourth proportional to 1,003.51, 1,387.52 and 987.85 is: 1,365.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,003.51 : 1,387.52 = 987.85 : x
  2. Step 2: Convert to fraction form
    1,003.51/1,387.52 = 987.85/x
  3. Step 3: Cross multiply
    1,003.51x = 1,387.52 × 987.85
  4. Step 4: Simplify right side
    1,003.51x = 1,370,656.69
  5. Step 5: Solve for x
    x = 1,370,656.69/1,003.51
  6. Step 6: Final answer
    x = 1,365.86

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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.