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Finding the Fourth Proportional to 815.60, 1,221.24 and 430.04

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Solution

The fourth proportional to 815.60, 1,221.24 and 430.04 is: 643.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.60 : 1,221.24 = 430.04 : x
  2. Step 2: Convert to fraction form
    815.60/1,221.24 = 430.04/x
  3. Step 3: Cross multiply
    815.60x = 1,221.24 × 430.04
  4. Step 4: Simplify right side
    815.60x = 525,182.05
  5. Step 5: Solve for x
    x = 525,182.05/815.60
  6. Step 6: Final answer
    x = 643.92

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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.