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Finding the Fourth Proportional to 486.15, 728.96 and 428.51

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Solution

The fourth proportional to 486.15, 728.96 and 428.51 is: 642.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.15 : 728.96 = 428.51 : x
  2. Step 2: Convert to fraction form
    486.15/728.96 = 428.51/x
  3. Step 3: Cross multiply
    486.15x = 728.96 × 428.51
  4. Step 4: Simplify right side
    486.15x = 312,360.86
  5. Step 5: Solve for x
    x = 312,360.86/486.15
  6. Step 6: Final answer
    x = 642.52

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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.