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Finding the Fourth Proportional to 810.50, 1,215.75 and 354.50

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Solution

The fourth proportional to 810.50, 1,215.75 and 354.50 is: 531.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.50 : 1,215.75 = 354.50 : x
  2. Step 2: Convert to fraction form
    810.50/1,215.75 = 354.50/x
  3. Step 3: Cross multiply
    810.50x = 1,215.75 × 354.50
  4. Step 4: Simplify right side
    810.50x = 430,983.38
  5. Step 5: Solve for x
    x = 430,983.38/810.50
  6. Step 6: Final answer
    x = 531.75

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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.