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Finding the Fourth Proportional to 780.51, 1,169.21 and 389.33

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Solution

The fourth proportional to 780.51, 1,169.21 and 389.33 is: 583.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.51 : 1,169.21 = 389.33 : x
  2. Step 2: Convert to fraction form
    780.51/1,169.21 = 389.33/x
  3. Step 3: Cross multiply
    780.51x = 1,169.21 × 389.33
  4. Step 4: Simplify right side
    780.51x = 455,200.74
  5. Step 5: Solve for x
    x = 455,200.74/780.51
  6. Step 6: Final answer
    x = 583.21

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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.