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Finding the Fourth Proportional to 815.64, 1,222.92 and 431.16

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Solution

The fourth proportional to 815.64, 1,222.92 and 431.16 is: 646.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.64 : 1,222.92 = 431.16 : x
  2. Step 2: Convert to fraction form
    815.64/1,222.92 = 431.16/x
  3. Step 3: Cross multiply
    815.64x = 1,222.92 × 431.16
  4. Step 4: Simplify right side
    815.64x = 527,274.19
  5. Step 5: Solve for x
    x = 527,274.19/815.64
  6. Step 6: Final answer
    x = 646.45

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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.