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Finding the Fourth Proportional to 661.42, 990.68 and 478.41

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Solution

The fourth proportional to 661.42, 990.68 and 478.41 is: 716.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.42 : 990.68 = 478.41 : x
  2. Step 2: Convert to fraction form
    661.42/990.68 = 478.41/x
  3. Step 3: Cross multiply
    661.42x = 990.68 × 478.41
  4. Step 4: Simplify right side
    661.42x = 473,947.80
  5. Step 5: Solve for x
    x = 473,947.80/661.42
  6. Step 6: Final answer
    x = 716.57

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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.