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Finding the Fourth Proportional to 780.13, 1,169.89 and 390.01

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Solution

The fourth proportional to 780.13, 1,169.89 and 390.01 is: 584.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.13 : 1,169.89 = 390.01 : x
  2. Step 2: Convert to fraction form
    780.13/1,169.89 = 390.01/x
  3. Step 3: Cross multiply
    780.13x = 1,169.89 × 390.01
  4. Step 4: Simplify right side
    780.13x = 456,268.80
  5. Step 5: Solve for x
    x = 456,268.80/780.13
  6. Step 6: Final answer
    x = 584.86

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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.