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Finding the Fourth Proportional to 745.28, 1,118 and 421.28

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Solution

The fourth proportional to 745.28, 1,118 and 421.28 is: 631.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    745.28 : 1,118 = 421.28 : x
  2. Step 2: Convert to fraction form
    745.28/1,118 = 421.28/x
  3. Step 3: Cross multiply
    745.28x = 1,118 × 421.28
  4. Step 4: Simplify right side
    745.28x = 470,991.04
  5. Step 5: Solve for x
    x = 470,991.04/745.28
  6. Step 6: Final answer
    x = 631.97

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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.