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Finding the Fourth Proportional to 903.70, 1,247.16 and 642.88

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Solution

The fourth proportional to 903.70, 1,247.16 and 642.88 is: 887.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    903.70 : 1,247.16 = 642.88 : x
  2. Step 2: Convert to fraction form
    903.70/1,247.16 = 642.88/x
  3. Step 3: Cross multiply
    903.70x = 1,247.16 × 642.88
  4. Step 4: Simplify right side
    903.70x = 801,774.22
  5. Step 5: Solve for x
    x = 801,774.22/903.70
  6. Step 6: Final answer
    x = 887.21

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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.