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Finding the Fourth Proportional to 815.70, 1,223.16 and 260.25

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Solution

The fourth proportional to 815.70, 1,223.16 and 260.25 is: 390.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.70 : 1,223.16 = 260.25 : x
  2. Step 2: Convert to fraction form
    815.70/1,223.16 = 260.25/x
  3. Step 3: Cross multiply
    815.70x = 1,223.16 × 260.25
  4. Step 4: Simplify right side
    815.70x = 318,327.39
  5. Step 5: Solve for x
    x = 318,327.39/815.70
  6. Step 6: Final answer
    x = 390.25

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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.