All you need to do is multiply 3 yards by 10 yards to get 30 square yards.
Odd.................................

Multiplication by 10ⁿ → move decimal n places to the right.
Multiplication by 10⁻ⁿ → move decimal n places to the left.
For n ∈ N
Area of a triangle = 1/2 x base x height
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Find Height :
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3.75 = 1/2 x 2.5 x height
3.75 = 1.25 x height
height = 3.75 ÷ 1.25
height = 3 meters
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Answer: The height is 3 meters.
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Use Google or Wolfram Alpha