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Finding the Fourth Proportional to 780.55, 1,170.96 and 311.89

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Solution

The fourth proportional to 780.55, 1,170.96 and 311.89 is: 467.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.55 : 1,170.96 = 311.89 : x
  2. Step 2: Convert to fraction form
    780.55/1,170.96 = 311.89/x
  3. Step 3: Cross multiply
    780.55x = 1,170.96 × 311.89
  4. Step 4: Simplify right side
    780.55x = 365,207.79
  5. Step 5: Solve for x
    x = 365,207.79/780.55
  6. Step 6: Final answer
    x = 467.89

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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.