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Finding the Fourth Proportional to 643.16, 965.21 and 278.21

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Solution

The fourth proportional to 643.16, 965.21 and 278.21 is: 417.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.16 : 965.21 = 278.21 : x
  2. Step 2: Convert to fraction form
    643.16/965.21 = 278.21/x
  3. Step 3: Cross multiply
    643.16x = 965.21 × 278.21
  4. Step 4: Simplify right side
    643.16x = 268,532.10
  5. Step 5: Solve for x
    x = 268,532.10/643.16
  6. Step 6: Final answer
    x = 417.52

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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.