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Finding the Fourth Proportional to 813.40, 1,220.10 and 692.20

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Solution

The fourth proportional to 813.40, 1,220.10 and 692.20 is: 1,038.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.40 : 1,220.10 = 692.20 : x
  2. Step 2: Convert to fraction form
    813.40/1,220.10 = 692.20/x
  3. Step 3: Cross multiply
    813.40x = 1,220.10 × 692.20
  4. Step 4: Simplify right side
    813.40x = 844,553.22
  5. Step 5: Solve for x
    x = 844,553.22/813.40
  6. Step 6: Final answer
    x = 1,038.30

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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.