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Finding the Fourth Proportional to 991.38, 1,368 and 549.21

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Solution

The fourth proportional to 991.38, 1,368 and 549.21 is: 757.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.38 : 1,368 = 549.21 : x
  2. Step 2: Convert to fraction form
    991.38/1,368 = 549.21/x
  3. Step 3: Cross multiply
    991.38x = 1,368 × 549.21
  4. Step 4: Simplify right side
    991.38x = 751,319.28
  5. Step 5: Solve for x
    x = 751,319.28/991.38
  6. Step 6: Final answer
    x = 757.85

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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.