complete question:
The picture below is the complete question.
Answer:
base of the triangles = 3 cm
Explanation:
The trapezoid was broken into 2 congruent triangles and a rectangle. The 2 triangle have a height of 12 cm . The rectangle has a height of 12 cm and width of 14 cm .
The base length of the triangle can be computed as follows.
Note a congruent triangle have exactly the same three sides and exactly the same three angles.
area of a triangle = 1/2 × base × height
From the area of the trapezoid one can calculate the sides of the triangle.
area of the trapezoid = 1/2 × (a + b)h
where
a = top side
b = base side
h = height
area of the trapezoid = 1/2 × (a + b)h
area of the trapezoid = 1/2 × (14 + 20)12
area of the trapezoid = 1/2 × 34 × 12
area of the trapezoid = 34 × 6
area of the trapezoid = 204 cm²
204 = area of the triangles + area of the rectangle
204 =2 (1/2bh) + lw
where
b = base of triangle
h = height of triangle
l = length of rectangle
w = width of rectangle
204 = bh + (14 × 12)
204 = 12b + 168
12b = 204 - 168
12b = 36
divide both sides by 12
b = 36/12
b = 3 cm
base of the triangles = 3 cm