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Finding the Fourth Proportional to 912.20, 1,368.30 and 521.80

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Solution

The fourth proportional to 912.20, 1,368.30 and 521.80 is: 782.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    912.20 : 1,368.30 = 521.80 : x
  2. Step 2: Convert to fraction form
    912.20/1,368.30 = 521.80/x
  3. Step 3: Cross multiply
    912.20x = 1,368.30 × 521.80
  4. Step 4: Simplify right side
    912.20x = 713,978.94
  5. Step 5: Solve for x
    x = 713,978.94/912.20
  6. Step 6: Final answer
    x = 782.70

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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.