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Finding the Fourth Proportional to 816.90, 1,122.29 and 669.21

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Solution

The fourth proportional to 816.90, 1,122.29 and 669.21 is: 919.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.90 : 1,122.29 = 669.21 : x
  2. Step 2: Convert to fraction form
    816.90/1,122.29 = 669.21/x
  3. Step 3: Cross multiply
    816.90x = 1,122.29 × 669.21
  4. Step 4: Simplify right side
    816.90x = 751,044.34
  5. Step 5: Solve for x
    x = 751,044.34/816.90
  6. Step 6: Final answer
    x = 919.38

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.