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Finding the Fourth Proportional to 647.21, 894.15 and 642.35

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Solution

The fourth proportional to 647.21, 894.15 and 642.35 is: 887.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    647.21 : 894.15 = 642.35 : x
  2. Step 2: Convert to fraction form
    647.21/894.15 = 642.35/x
  3. Step 3: Cross multiply
    647.21x = 894.15 × 642.35
  4. Step 4: Simplify right side
    647.21x = 574,357.25
  5. Step 5: Solve for x
    x = 574,357.25/647.21
  6. Step 6: Final answer
    x = 887.44

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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.