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Finding the Fourth Proportional to 515.11, 711.18 and 420.81

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Solution

The fourth proportional to 515.11, 711.18 and 420.81 is: 580.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.11 : 711.18 = 420.81 : x
  2. Step 2: Convert to fraction form
    515.11/711.18 = 420.81/x
  3. Step 3: Cross multiply
    515.11x = 711.18 × 420.81
  4. Step 4: Simplify right side
    515.11x = 299,271.84
  5. Step 5: Solve for x
    x = 299,271.84/515.11
  6. Step 6: Final answer
    x = 580.99

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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.