Answer:
B
Step-by-step explanation:
The perimeter is the sum of the 3 sides. thus
perimeter = 12 + 12 + 9.7 = 33.7 mm
The area (A) of a triangle is calculated as
A = 0.5 × base × perpendicular height
Here base = 12 and height = 9
A = 0.5 × 12 × 9 = 6 × 9 = 54 mm²
