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Finding the Fourth Proportional to 660.29, 990.50 and 386.40

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Solution

The fourth proportional to 660.29, 990.50 and 386.40 is: 579.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.29 : 990.50 = 386.40 : x
  2. Step 2: Convert to fraction form
    660.29/990.50 = 386.40/x
  3. Step 3: Cross multiply
    660.29x = 990.50 × 386.40
  4. Step 4: Simplify right side
    660.29x = 382,730.98
  5. Step 5: Solve for x
    x = 382,730.98/660.29
  6. Step 6: Final answer
    x = 579.65

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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.