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Finding the Fourth Proportional to 991.78, 1,363.71 and 886.21

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Solution

The fourth proportional to 991.78, 1,363.71 and 886.21 is: 1,218.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.78 : 1,363.71 = 886.21 : x
  2. Step 2: Convert to fraction form
    991.78/1,363.71 = 886.21/x
  3. Step 3: Cross multiply
    991.78x = 1,363.71 × 886.21
  4. Step 4: Simplify right side
    991.78x = 1,208,533.44
  5. Step 5: Solve for x
    x = 1,208,533.44/991.78
  6. Step 6: Final answer
    x = 1,218.55

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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.