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Finding the Fourth Proportional to 815, 1,222.50 and 207

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Solution

The fourth proportional to 815, 1,222.50 and 207 is: 310.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    815 : 1,222.50 = 207 : x
  2. Step 2: Convert to fraction form
    815/1,222.50 = 207/x
  3. Step 3: Cross multiply
    815x = 1,222.50 × 207
  4. Step 4: Simplify right side
    815x = 253,057.50
  5. Step 5: Solve for x
    x = 253,057.50/815
  6. Step 6: Final answer
    x = 310.50

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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.