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Finding the Fourth Proportional to 991.66, 1,368.50 and 618.64

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Solution

The fourth proportional to 991.66, 1,368.50 and 618.64 is: 853.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.66 : 1,368.50 = 618.64 : x
  2. Step 2: Convert to fraction form
    991.66/1,368.50 = 618.64/x
  3. Step 3: Cross multiply
    991.66x = 1,368.50 × 618.64
  4. Step 4: Simplify right side
    991.66x = 846,605.75
  5. Step 5: Solve for x
    x = 846,605.75/991.66
  6. Step 6: Final answer
    x = 853.73

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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.