Which value must be added to the expression x2 + 12x to make it a perfect-square trinomial?
1 answer:
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Answer:
- B. 191.4 m²
Step-by-step explanation:
Split the trapezoid as pictured below
Find its height and the upper base, then find the area of the trapezoid.
There are 3 pieces, two of them are 45°×45° and 30°×60°×90° triangles
- The ratio of sides of a 30°×60°×90° triangle is 1 : √3 : 2
- The legs of a 45x45 triangle are equal
<u>The above mentioned properties give us:</u>
- h = 16/2 = 8 m
- b = 8√3 ≈ 13.85 m
- a = h = 8 m
<u>Now find the area:</u>
- A = 1/2( 13 + 8 + 13.85 + 13)*8 = 191.4 m²
Correct choice is B
