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Finding the Fourth Proportional to 991.27, 1,368.62 and 618.40

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Solution

The fourth proportional to 991.27, 1,368.62 and 618.40 is: 853.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.27 : 1,368.62 = 618.40 : x
  2. Step 2: Convert to fraction form
    991.27/1,368.62 = 618.40/x
  3. Step 3: Cross multiply
    991.27x = 1,368.62 × 618.40
  4. Step 4: Simplify right side
    991.27x = 846,354.61
  5. Step 5: Solve for x
    x = 846,354.61/991.27
  6. Step 6: Final answer
    x = 853.81

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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.