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Finding the Fourth Proportional to 821.80, 1,134.18 and 644.20

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Solution

The fourth proportional to 821.80, 1,134.18 and 644.20 is: 889.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.80 : 1,134.18 = 644.20 : x
  2. Step 2: Convert to fraction form
    821.80/1,134.18 = 644.20/x
  3. Step 3: Cross multiply
    821.80x = 1,134.18 × 644.20
  4. Step 4: Simplify right side
    821.80x = 730,638.76
  5. Step 5: Solve for x
    x = 730,638.76/821.80
  6. Step 6: Final answer
    x = 889.07

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1.5x scale

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.