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Finding the Fourth Proportional to 660.21, 989.99 and 215.34

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Solution

The fourth proportional to 660.21, 989.99 and 215.34 is: 322.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.21 : 989.99 = 215.34 : x
  2. Step 2: Convert to fraction form
    660.21/989.99 = 215.34/x
  3. Step 3: Cross multiply
    660.21x = 989.99 × 215.34
  4. Step 4: Simplify right side
    660.21x = 213,184.45
  5. Step 5: Solve for x
    x = 213,184.45/660.21
  6. Step 6: Final answer
    x = 322.90

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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.