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Finding the Fourth Proportional to 1,382.39, 1,907.60 and 815.45

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Solution

The fourth proportional to 1,382.39, 1,907.60 and 815.45 is: 1,125.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,382.39 : 1,907.60 = 815.45 : x
  2. Step 2: Convert to fraction form
    1,382.39/1,907.60 = 815.45/x
  3. Step 3: Cross multiply
    1,382.39x = 1,907.60 × 815.45
  4. Step 4: Simplify right side
    1,382.39x = 1,555,538.80
  5. Step 5: Solve for x
    x = 1,555,538.80/1,382.39
  6. Step 6: Final answer
    x = 1,125.26

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Half scale
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1.5x scale

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.