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Finding the Fourth Proportional to 1,225, 1,690.50 and 811.08

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Solution

The fourth proportional to 1,225, 1,690.50 and 811.08 is: 1,119.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,225 : 1,690.50 = 811.08 : x
  2. Step 2: Convert to fraction form
    1,225/1,690.50 = 811.08/x
  3. Step 3: Cross multiply
    1,225x = 1,690.50 × 811.08
  4. Step 4: Simplify right side
    1,225x = 1,371,130.74
  5. Step 5: Solve for x
    x = 1,371,130.74/1,225
  6. Step 6: Final answer
    x = 1,119.29

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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.