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Finding the Fourth Proportional to 513.72, 709.20 and 317.40

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Solution

The fourth proportional to 513.72, 709.20 and 317.40 is: 438.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    513.72 : 709.20 = 317.40 : x
  2. Step 2: Convert to fraction form
    513.72/709.20 = 317.40/x
  3. Step 3: Cross multiply
    513.72x = 709.20 × 317.40
  4. Step 4: Simplify right side
    513.72x = 225,100.08
  5. Step 5: Solve for x
    x = 225,100.08/513.72
  6. Step 6: Final answer
    x = 438.18

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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.