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Finding the Fourth Proportional to 780.45, 1,171.08 and 520.65

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Solution

The fourth proportional to 780.45, 1,171.08 and 520.65 is: 781.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.45 : 1,171.08 = 520.65 : x
  2. Step 2: Convert to fraction form
    780.45/1,171.08 = 520.65/x
  3. Step 3: Cross multiply
    780.45x = 1,171.08 × 520.65
  4. Step 4: Simplify right side
    780.45x = 609,722.80
  5. Step 5: Solve for x
    x = 609,722.80/780.45
  6. Step 6: Final answer
    x = 781.25

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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.