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Finding the Fourth Proportional to 781.20, 1,168.80 and 705.60

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Solution

The fourth proportional to 781.20, 1,168.80 and 705.60 is: 1,055.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.20 : 1,168.80 = 705.60 : x
  2. Step 2: Convert to fraction form
    781.20/1,168.80 = 705.60/x
  3. Step 3: Cross multiply
    781.20x = 1,168.80 × 705.60
  4. Step 4: Simplify right side
    781.20x = 824,705.28
  5. Step 5: Solve for x
    x = 824,705.28/781.20
  6. Step 6: Final answer
    x = 1,055.69

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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.