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Finding the Fourth Proportional to 991.81, 1,368.12 and 613.85

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Solution

The fourth proportional to 991.81, 1,368.12 and 613.85 is: 846.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    991.81 : 1,368.12 = 613.85 : x
  2. Step 2: Convert to fraction form
    991.81/1,368.12 = 613.85/x
  3. Step 3: Cross multiply
    991.81x = 1,368.12 × 613.85
  4. Step 4: Simplify right side
    991.81x = 839,816.32
  5. Step 5: Solve for x
    x = 839,816.32/991.81
  6. Step 6: Final answer
    x = 846.75

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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.