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Finding the Fourth Proportional to 1,109.68, 1,661.29 and 780.19

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Solution

The fourth proportional to 1,109.68, 1,661.29 and 780.19 is: 1,168.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,109.68 : 1,661.29 = 780.19 : x
  2. Step 2: Convert to fraction form
    1,109.68/1,661.29 = 780.19/x
  3. Step 3: Cross multiply
    1,109.68x = 1,661.29 × 780.19
  4. Step 4: Simplify right side
    1,109.68x = 1,296,121.85
  5. Step 5: Solve for x
    x = 1,296,121.85/1,109.68
  6. Step 6: Final answer
    x = 1,168.01

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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.