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Finding the Fourth Proportional to 1,007.10, 1,389.12 and 820.60

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Solution

The fourth proportional to 1,007.10, 1,389.12 and 820.60 is: 1,131.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,007.10 : 1,389.12 = 820.60 : x
  2. Step 2: Convert to fraction form
    1,007.10/1,389.12 = 820.60/x
  3. Step 3: Cross multiply
    1,007.10x = 1,389.12 × 820.60
  4. Step 4: Simplify right side
    1,007.10x = 1,139,905.32
  5. Step 5: Solve for x
    x = 1,139,905.32/1,007.10
  6. Step 6: Final answer
    x = 1,131.87

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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.