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Finding the Fourth Proportional to 661.01, 989.91 and 386.28

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Solution

The fourth proportional to 661.01, 989.91 and 386.28 is: 578.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.01 : 989.91 = 386.28 : x
  2. Step 2: Convert to fraction form
    661.01/989.91 = 386.28/x
  3. Step 3: Cross multiply
    661.01x = 989.91 × 386.28
  4. Step 4: Simplify right side
    661.01x = 382,382.43
  5. Step 5: Solve for x
    x = 382,382.43/661.01
  6. Step 6: Final answer
    x = 578.49

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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.