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Finding the Fourth Proportional to 661.65, 991.42 and 558.45

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Solution

The fourth proportional to 661.65, 991.42 and 558.45 is: 836.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.65 : 991.42 = 558.45 : x
  2. Step 2: Convert to fraction form
    661.65/991.42 = 558.45/x
  3. Step 3: Cross multiply
    661.65x = 991.42 × 558.45
  4. Step 4: Simplify right side
    661.65x = 553,658.50
  5. Step 5: Solve for x
    x = 553,658.50/661.65
  6. Step 6: Final answer
    x = 836.78

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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.