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Finding the Fourth Proportional to 815.64, 1,223.72 and 328.72

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Solution

The fourth proportional to 815.64, 1,223.72 and 328.72 is: 493.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.64 : 1,223.72 = 328.72 : x
  2. Step 2: Convert to fraction form
    815.64/1,223.72 = 328.72/x
  3. Step 3: Cross multiply
    815.64x = 1,223.72 × 328.72
  4. Step 4: Simplify right side
    815.64x = 402,261.24
  5. Step 5: Solve for x
    x = 402,261.24/815.64
  6. Step 6: Final answer
    x = 493.18

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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.