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Finding the Fourth Proportional to 780.84, 1,170.81 and 665.10

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Solution

The fourth proportional to 780.84, 1,170.81 and 665.10 is: 997.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.84 : 1,170.81 = 665.10 : x
  2. Step 2: Convert to fraction form
    780.84/1,170.81 = 665.10/x
  3. Step 3: Cross multiply
    780.84x = 1,170.81 × 665.10
  4. Step 4: Simplify right side
    780.84x = 778,705.73
  5. Step 5: Solve for x
    x = 778,705.73/780.84
  6. Step 6: Final answer
    x = 997.27

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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.