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Finding the Fourth Proportional to 515.40, 711.08 and 305.61

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Solution

The fourth proportional to 515.40, 711.08 and 305.61 is: 421.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.40 : 711.08 = 305.61 : x
  2. Step 2: Convert to fraction form
    515.40/711.08 = 305.61/x
  3. Step 3: Cross multiply
    515.40x = 711.08 × 305.61
  4. Step 4: Simplify right side
    515.40x = 217,310.11
  5. Step 5: Solve for x
    x = 217,310.11/515.40
  6. Step 6: Final answer
    x = 421.64

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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.