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Finding the Fourth Proportional to 681.21, 1,015.91 and 615.60

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Solution

The fourth proportional to 681.21, 1,015.91 and 615.60 is: 918.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.21 : 1,015.91 = 615.60 : x
  2. Step 2: Convert to fraction form
    681.21/1,015.91 = 615.60/x
  3. Step 3: Cross multiply
    681.21x = 1,015.91 × 615.60
  4. Step 4: Simplify right side
    681.21x = 625,394.20
  5. Step 5: Solve for x
    x = 625,394.20/681.21
  6. Step 6: Final answer
    x = 918.06

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.