If the height of a triangle is decreased by 40% and its base is increased by 40%. What will be the effect on its area?

16% decrease

Area of the triangle = \(\frac{ 1}{ 2}\) x b x h

Assuming base to be 100 and height as 100. So, the area = \(\frac{ 1}{ 2}\) x 100 x 100 = 5000 

After increase in the base by 40% and decrease in the height of the triangle by 40%, the area becomes:

Height = 60 and base = 140

Area = \(\frac{ 1}{ 2}\) x 140 x 60 = 4200

Reduction in the area: 5000 - 4200 = 800

Thus, reduction in percentage form = \(\frac{ 800}{5000 }\) x 100 = 16% reduction