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Finding the Fourth Proportional to 661.13, 990.81 and 515.06

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Solution

The fourth proportional to 661.13, 990.81 and 515.06 is: 771.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.13 : 990.81 = 515.06 : x
  2. Step 2: Convert to fraction form
    661.13/990.81 = 515.06/x
  3. Step 3: Cross multiply
    661.13x = 990.81 × 515.06
  4. Step 4: Simplify right side
    661.13x = 510,326.60
  5. Step 5: Solve for x
    x = 510,326.60/661.13
  6. Step 6: Final answer
    x = 771.90

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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.