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Finding the Fourth Proportional to 1,389.69, 1,918.13 and 865.44

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Solution

The fourth proportional to 1,389.69, 1,918.13 and 865.44 is: 1,194.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.69 : 1,918.13 = 865.44 : x
  2. Step 2: Convert to fraction form
    1,389.69/1,918.13 = 865.44/x
  3. Step 3: Cross multiply
    1,389.69x = 1,918.13 × 865.44
  4. Step 4: Simplify right side
    1,389.69x = 1,660,022.10
  5. Step 5: Solve for x
    x = 1,660,022.10/1,389.69
  6. Step 6: Final answer
    x = 1,194.53

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1.5x scale

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.