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Finding the Fourth Proportional to 660.55, 990.19 and 386.59

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Solution

The fourth proportional to 660.55, 990.19 and 386.59 is: 579.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.55 : 990.19 = 386.59 : x
  2. Step 2: Convert to fraction form
    660.55/990.19 = 386.59/x
  3. Step 3: Cross multiply
    660.55x = 990.19 × 386.59
  4. Step 4: Simplify right side
    660.55x = 382,797.55
  5. Step 5: Solve for x
    x = 382,797.55/660.55
  6. Step 6: Final answer
    x = 579.51

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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.