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Finding the Fourth Proportional to 780.17, 1,170.78 and 415.22

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Solution

The fourth proportional to 780.17, 1,170.78 and 415.22 is: 623.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.17 : 1,170.78 = 415.22 : x
  2. Step 2: Convert to fraction form
    780.17/1,170.78 = 415.22/x
  3. Step 3: Cross multiply
    780.17x = 1,170.78 × 415.22
  4. Step 4: Simplify right side
    780.17x = 486,134.20
  5. Step 5: Solve for x
    x = 486,134.20/780.17
  6. Step 6: Final answer
    x = 623.11

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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.