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Finding the Fourth Proportional to 661.20, 990.60 and 538.80

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Solution

The fourth proportional to 661.20, 990.60 and 538.80 is: 807.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.20 : 990.60 = 538.80 : x
  2. Step 2: Convert to fraction form
    661.20/990.60 = 538.80/x
  3. Step 3: Cross multiply
    661.20x = 990.60 × 538.80
  4. Step 4: Simplify right side
    661.20x = 533,735.28
  5. Step 5: Solve for x
    x = 533,735.28/661.20
  6. Step 6: Final answer
    x = 807.22

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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.