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Finding the Fourth Proportional to 811.55, 1,215.30 and 775.10

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Solution

The fourth proportional to 811.55, 1,215.30 and 775.10 is: 1,160.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.55 : 1,215.30 = 775.10 : x
  2. Step 2: Convert to fraction form
    811.55/1,215.30 = 775.10/x
  3. Step 3: Cross multiply
    811.55x = 1,215.30 × 775.10
  4. Step 4: Simplify right side
    811.55x = 941,979.03
  5. Step 5: Solve for x
    x = 941,979.03/811.55
  6. Step 6: Final answer
    x = 1,160.72

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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.