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Finding the Fourth Proportional to 904.50, 1,247.79 and 642.66

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Solution

The fourth proportional to 904.50, 1,247.79 and 642.66 is: 886.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    904.50 : 1,247.79 = 642.66 : x
  2. Step 2: Convert to fraction form
    904.50/1,247.79 = 642.66/x
  3. Step 3: Cross multiply
    904.50x = 1,247.79 × 642.66
  4. Step 4: Simplify right side
    904.50x = 801,904.72
  5. Step 5: Solve for x
    x = 801,904.72/904.50
  6. Step 6: Final answer
    x = 886.57

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.