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Finding the Fourth Proportional to 780.22, 1,172.15 and 670.87

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Solution

The fourth proportional to 780.22, 1,172.15 and 670.87 is: 1,007.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.22 : 1,172.15 = 670.87 : x
  2. Step 2: Convert to fraction form
    780.22/1,172.15 = 670.87/x
  3. Step 3: Cross multiply
    780.22x = 1,172.15 × 670.87
  4. Step 4: Simplify right side
    780.22x = 786,359.02
  5. Step 5: Solve for x
    x = 786,359.02/780.22
  6. Step 6: Final answer
    x = 1,007.87

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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.