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Finding the Fourth Proportional to 780.75, 1,170.27 and 689.67

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Solution

The fourth proportional to 780.75, 1,170.27 and 689.67 is: 1,033.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.75 : 1,170.27 = 689.67 : x
  2. Step 2: Convert to fraction form
    780.75/1,170.27 = 689.67/x
  3. Step 3: Cross multiply
    780.75x = 1,170.27 × 689.67
  4. Step 4: Simplify right side
    780.75x = 807,100.11
  5. Step 5: Solve for x
    x = 807,100.11/780.75
  6. Step 6: Final answer
    x = 1,033.75

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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.