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Finding the Fourth Proportional to 838.48, 1,257 and 405.40

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Solution

The fourth proportional to 838.48, 1,257 and 405.40 is: 607.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    838.48 : 1,257 = 405.40 : x
  2. Step 2: Convert to fraction form
    838.48/1,257 = 405.40/x
  3. Step 3: Cross multiply
    838.48x = 1,257 × 405.40
  4. Step 4: Simplify right side
    838.48x = 509,587.80
  5. Step 5: Solve for x
    x = 509,587.80/838.48
  6. Step 6: Final answer
    x = 607.75

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.