Question

area of a triangle is 280cm^2,if base of the triangle is 70cm, do d it's corresponding altitude

Answer 1

the area of the triangle is its base multiplied by its "altitude", height that is, and divided by 2:
area = base*height/2
therefore
height = 2*area/base
plug in the data:
height = 2*280/70
height = 8 cm

Answer 2

Answer: 8 cm

Explanation:  

Given that Area of a triangle = 280cm^2

Base of the triangle = 70cm

Area of triangle = ½ * base * height  

(Height is also known as the altitude)

Substituting the given values in the formula stated above  

280 = ½ * 70 * h

280 * 2 = 70 * h

560 = 70 * h

560 / 70 = h

8 cm = h