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Finding the Fourth Proportional to 781.80, 1,172.70 and 706.20

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Solution

The fourth proportional to 781.80, 1,172.70 and 706.20 is: 1,059.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.80 : 1,172.70 = 706.20 : x
  2. Step 2: Convert to fraction form
    781.80/1,172.70 = 706.20/x
  3. Step 3: Cross multiply
    781.80x = 1,172.70 × 706.20
  4. Step 4: Simplify right side
    781.80x = 828,160.74
  5. Step 5: Solve for x
    x = 828,160.74/781.80
  6. Step 6: Final answer
    x = 1,059.30

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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.