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Finding the Fourth Proportional to 752.34, 1,038.21 and 420.78

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Solution

The fourth proportional to 752.34, 1,038.21 and 420.78 is: 580.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    752.34 : 1,038.21 = 420.78 : x
  2. Step 2: Convert to fraction form
    752.34/1,038.21 = 420.78/x
  3. Step 3: Cross multiply
    752.34x = 1,038.21 × 420.78
  4. Step 4: Simplify right side
    752.34x = 436,858.00
  5. Step 5: Solve for x
    x = 436,858.00/752.34
  6. Step 6: Final answer
    x = 580.67

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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.