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Finding the Fourth Proportional to 991.70, 1,371.15 and 868.68

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Solution

The fourth proportional to 991.70, 1,371.15 and 868.68 is: 1,201.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.70 : 1,371.15 = 868.68 : x
  2. Step 2: Convert to fraction form
    991.70/1,371.15 = 868.68/x
  3. Step 3: Cross multiply
    991.70x = 1,371.15 × 868.68
  4. Step 4: Simplify right side
    991.70x = 1,191,090.58
  5. Step 5: Solve for x
    x = 1,191,090.58/991.70
  6. Step 6: Final answer
    x = 1,201.06

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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.