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Finding the Fourth Proportional to 919.60, 1,380.30 and 457.90

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Solution

The fourth proportional to 919.60, 1,380.30 and 457.90 is: 687.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.60 : 1,380.30 = 457.90 : x
  2. Step 2: Convert to fraction form
    919.60/1,380.30 = 457.90/x
  3. Step 3: Cross multiply
    919.60x = 1,380.30 × 457.90
  4. Step 4: Simplify right side
    919.60x = 632,039.37
  5. Step 5: Solve for x
    x = 632,039.37/919.60
  6. Step 6: Final answer
    x = 687.30

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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.