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Finding the Fourth Proportional to 515.20, 768.64 and 486.40

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Solution

The fourth proportional to 515.20, 768.64 and 486.40 is: 725.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.20 : 768.64 = 486.40 : x
  2. Step 2: Convert to fraction form
    515.20/768.64 = 486.40/x
  3. Step 3: Cross multiply
    515.20x = 768.64 × 486.40
  4. Step 4: Simplify right side
    515.20x = 373,866.50
  5. Step 5: Solve for x
    x = 373,866.50/515.20
  6. Step 6: Final answer
    x = 725.67

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.