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Finding the Fourth Proportional to 787.80, 1,181.70 and 712.20

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Solution

The fourth proportional to 787.80, 1,181.70 and 712.20 is: 1,068.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    787.80 : 1,181.70 = 712.20 : x
  2. Step 2: Convert to fraction form
    787.80/1,181.70 = 712.20/x
  3. Step 3: Cross multiply
    787.80x = 1,181.70 × 712.20
  4. Step 4: Simplify right side
    787.80x = 841,606.74
  5. Step 5: Solve for x
    x = 841,606.74/787.80
  6. Step 6: Final answer
    x = 1,068.30

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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.