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Finding the Fourth Proportional to 661.36, 991.68 and 490

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Solution

The fourth proportional to 661.36, 991.68 and 490 is: 734.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.36 : 991.68 = 490 : x
  2. Step 2: Convert to fraction form
    661.36/991.68 = 490/x
  3. Step 3: Cross multiply
    661.36x = 991.68 × 490
  4. Step 4: Simplify right side
    661.36x = 485,923.20
  5. Step 5: Solve for x
    x = 485,923.20/661.36
  6. Step 6: Final answer
    x = 734.73

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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.