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Finding the Fourth Proportional to 991.78, 1,368.72 and 549.74

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Solution

The fourth proportional to 991.78, 1,368.72 and 549.74 is: 758.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.78 : 1,368.72 = 549.74 : x
  2. Step 2: Convert to fraction form
    991.78/1,368.72 = 549.74/x
  3. Step 3: Cross multiply
    991.78x = 1,368.72 × 549.74
  4. Step 4: Simplify right side
    991.78x = 752,440.13
  5. Step 5: Solve for x
    x = 752,440.13/991.78
  6. Step 6: Final answer
    x = 758.68

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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.