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Finding the Fourth Proportional to 804.90, 1,207.80 and 415.20

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Solution

The fourth proportional to 804.90, 1,207.80 and 415.20 is: 623.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    804.90 : 1,207.80 = 415.20 : x
  2. Step 2: Convert to fraction form
    804.90/1,207.80 = 415.20/x
  3. Step 3: Cross multiply
    804.90x = 1,207.80 × 415.20
  4. Step 4: Simplify right side
    804.90x = 501,478.56
  5. Step 5: Solve for x
    x = 501,478.56/804.90
  6. Step 6: Final answer
    x = 623.03

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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.