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Finding the Fourth Proportional to 1,328.69, 1,992.42 and 781.13

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Solution

The fourth proportional to 1,328.69, 1,992.42 and 781.13 is: 1,171.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,328.69 : 1,992.42 = 781.13 : x
  2. Step 2: Convert to fraction form
    1,328.69/1,992.42 = 781.13/x
  3. Step 3: Cross multiply
    1,328.69x = 1,992.42 × 781.13
  4. Step 4: Simplify right side
    1,328.69x = 1,556,329.07
  5. Step 5: Solve for x
    x = 1,556,329.07/1,328.69
  6. Step 6: Final answer
    x = 1,171.33

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.