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Finding the Fourth Proportional to 752.31, 1,038.20 and 420.75

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Solution

The fourth proportional to 752.31, 1,038.20 and 420.75 is: 580.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    752.31 : 1,038.20 = 420.75 : x
  2. Step 2: Convert to fraction form
    752.31/1,038.20 = 420.75/x
  3. Step 3: Cross multiply
    752.31x = 1,038.20 × 420.75
  4. Step 4: Simplify right side
    752.31x = 436,820.55
  5. Step 5: Solve for x
    x = 436,820.55/752.31
  6. Step 6: Final answer
    x = 580.64

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Double scale
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1.5x scale

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.