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Finding the Fourth Proportional to 815.53, 1,221.64 and 651.28

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Solution

The fourth proportional to 815.53, 1,221.64 and 651.28 is: 975.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.53 : 1,221.64 = 651.28 : x
  2. Step 2: Convert to fraction form
    815.53/1,221.64 = 651.28/x
  3. Step 3: Cross multiply
    815.53x = 1,221.64 × 651.28
  4. Step 4: Simplify right side
    815.53x = 795,623.59
  5. Step 5: Solve for x
    x = 795,623.59/815.53
  6. Step 6: Final answer
    x = 975.59

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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.