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Finding the Fourth Proportional to 317.40, 438.21 and 251.70

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Solution

The fourth proportional to 317.40, 438.21 and 251.70 is: 347.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    317.40 : 438.21 = 251.70 : x
  2. Step 2: Convert to fraction form
    317.40/438.21 = 251.70/x
  3. Step 3: Cross multiply
    317.40x = 438.21 × 251.70
  4. Step 4: Simplify right side
    317.40x = 110,297.46
  5. Step 5: Solve for x
    x = 110,297.46/317.40
  6. Step 6: Final answer
    x = 347.50

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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.