Final answer:
The perimeter of a triangle is given, but more information is needed to find the value of a.
Step-by-step explanation:
The perimeter of a triangle is the sum of the lengths of its three sides. In this case, the perimeter is given as 70 cm. Let's assume the lengths of the sides of the triangle are a, b, and c. So, a + b + c = 70.
The area of a triangle is given by the formula 1/2 * base * height. Since the base is not provided, we cannot directly find the value of a. We would need more information to determine the value of a.
Therefore, without more information, it is not possible to find the value of a.