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Finding the Fourth Proportional to 1,187.80, 1,780.50 and 538.20

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Solution

The fourth proportional to 1,187.80, 1,780.50 and 538.20 is: 806.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,187.80 : 1,780.50 = 538.20 : x
  2. Step 2: Convert to fraction form
    1,187.80/1,780.50 = 538.20/x
  3. Step 3: Cross multiply
    1,187.80x = 1,780.50 × 538.20
  4. Step 4: Simplify right side
    1,187.80x = 958,265.10
  5. Step 5: Solve for x
    x = 958,265.10/1,187.80
  6. Step 6: Final answer
    x = 806.76

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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.