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Finding the Fourth Proportional to 919.76, 1,378.40 and 456.86

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Solution

The fourth proportional to 919.76, 1,378.40 and 456.86 is: 684.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    919.76 : 1,378.40 = 456.86 : x
  2. Step 2: Convert to fraction form
    919.76/1,378.40 = 456.86/x
  3. Step 3: Cross multiply
    919.76x = 1,378.40 × 456.86
  4. Step 4: Simplify right side
    919.76x = 629,735.82
  5. Step 5: Solve for x
    x = 629,735.82/919.76
  6. Step 6: Final answer
    x = 684.67

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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.