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Finding the Fourth Proportional to 661.28, 990.60 and 314.95

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Solution

The fourth proportional to 661.28, 990.60 and 314.95 is: 471.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.28 : 990.60 = 314.95 : x
  2. Step 2: Convert to fraction form
    661.28/990.60 = 314.95/x
  3. Step 3: Cross multiply
    661.28x = 990.60 × 314.95
  4. Step 4: Simplify right side
    661.28x = 311,988.68
  5. Step 5: Solve for x
    x = 311,988.68/661.28
  6. Step 6: Final answer
    x = 471.80

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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.