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Finding the Fourth Proportional to 818.24, 1,225.20 and 687.20

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Solution

The fourth proportional to 818.24, 1,225.20 and 687.20 is: 1,028.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.24 : 1,225.20 = 687.20 : x
  2. Step 2: Convert to fraction form
    818.24/1,225.20 = 687.20/x
  3. Step 3: Cross multiply
    818.24x = 1,225.20 × 687.20
  4. Step 4: Simplify right side
    818.24x = 841,957.44
  5. Step 5: Solve for x
    x = 841,957.44/818.24
  6. Step 6: Final answer
    x = 1,028.99

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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.