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Finding the Fourth Proportional to 660.42, 990.67 and 386.30

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Solution

The fourth proportional to 660.42, 990.67 and 386.30 is: 579.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.42 : 990.67 = 386.30 : x
  2. Step 2: Convert to fraction form
    660.42/990.67 = 386.30/x
  3. Step 3: Cross multiply
    660.42x = 990.67 × 386.30
  4. Step 4: Simplify right side
    660.42x = 382,695.82
  5. Step 5: Solve for x
    x = 382,695.82/660.42
  6. Step 6: Final answer
    x = 579.47

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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.