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Finding the Fourth Proportional to 818, 1,225.54 and 642.64

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Solution

The fourth proportional to 818, 1,225.54 and 642.64 is: 962.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    818 : 1,225.54 = 642.64 : x
  2. Step 2: Convert to fraction form
    818/1,225.54 = 642.64/x
  3. Step 3: Cross multiply
    818x = 1,225.54 × 642.64
  4. Step 4: Simplify right side
    818x = 787,581.03
  5. Step 5: Solve for x
    x = 787,581.03/818
  6. Step 6: Final answer
    x = 962.81

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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.