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Finding the Fourth Proportional to 991.50, 1,370.91 and 868.51

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Solution

The fourth proportional to 991.50, 1,370.91 and 868.51 is: 1,200.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.50 : 1,370.91 = 868.51 : x
  2. Step 2: Convert to fraction form
    991.50/1,370.91 = 868.51/x
  3. Step 3: Cross multiply
    991.50x = 1,370.91 × 868.51
  4. Step 4: Simplify right side
    991.50x = 1,190,649.04
  5. Step 5: Solve for x
    x = 1,190,649.04/991.50
  6. Step 6: Final answer
    x = 1,200.86

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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.