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Finding the Fourth Proportional to 752.40, 1,128.12 and 319.12

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Solution

The fourth proportional to 752.40, 1,128.12 and 319.12 is: 478.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    752.40 : 1,128.12 = 319.12 : x
  2. Step 2: Convert to fraction form
    752.40/1,128.12 = 319.12/x
  3. Step 3: Cross multiply
    752.40x = 1,128.12 × 319.12
  4. Step 4: Simplify right side
    752.40x = 360,005.65
  5. Step 5: Solve for x
    x = 360,005.65/752.40
  6. Step 6: Final answer
    x = 478.48

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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.