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Finding the Fourth Proportional to 811.40, 1,215.36 and 348.57

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Solution

The fourth proportional to 811.40, 1,215.36 and 348.57 is: 522.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.40 : 1,215.36 = 348.57 : x
  2. Step 2: Convert to fraction form
    811.40/1,215.36 = 348.57/x
  3. Step 3: Cross multiply
    811.40x = 1,215.36 × 348.57
  4. Step 4: Simplify right side
    811.40x = 423,638.04
  5. Step 5: Solve for x
    x = 423,638.04/811.40
  6. Step 6: Final answer
    x = 522.11

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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.