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Finding the Fourth Proportional to 485.63, 728.47 and 138.93

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Solution

The fourth proportional to 485.63, 728.47 and 138.93 is: 208.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.63 : 728.47 = 138.93 : x
  2. Step 2: Convert to fraction form
    485.63/728.47 = 138.93/x
  3. Step 3: Cross multiply
    485.63x = 728.47 × 138.93
  4. Step 4: Simplify right side
    485.63x = 101,203.26
  5. Step 5: Solve for x
    x = 101,203.26/485.63
  6. Step 6: Final answer
    x = 208.40

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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.