Question 315523
The area of a rectangle is Base x Height. 

A triangle is the shape formed by taking half of a rectangle, so its area is 1/2 x Base x Height. 

{{{ A = (1/2) * B * H }}} 

B = 5 
H = 5 

{{{ A = (1/2) * 5 * 5}}} 

{{{ A = (1/2) * 25 }}} 

{{{ A = 12.5 }}}