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Finding the Fourth Proportional to 642.36, 964.50 and 521.40

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Solution

The fourth proportional to 642.36, 964.50 and 521.40 is: 782.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.36 : 964.50 = 521.40 : x
  2. Step 2: Convert to fraction form
    642.36/964.50 = 521.40/x
  3. Step 3: Cross multiply
    642.36x = 964.50 × 521.40
  4. Step 4: Simplify right side
    642.36x = 502,890.30
  5. Step 5: Solve for x
    x = 502,890.30/642.36
  6. Step 6: Final answer
    x = 782.88

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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.