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Finding the Fourth Proportional to 978.23, 1,349.81 and 558.51

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Solution

The fourth proportional to 978.23, 1,349.81 and 558.51 is: 770.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.23 : 1,349.81 = 558.51 : x
  2. Step 2: Convert to fraction form
    978.23/1,349.81 = 558.51/x
  3. Step 3: Cross multiply
    978.23x = 1,349.81 × 558.51
  4. Step 4: Simplify right side
    978.23x = 753,879.59
  5. Step 5: Solve for x
    x = 753,879.59/978.23
  6. Step 6: Final answer
    x = 770.66

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.