Why does that formula make sense?

Step-by-step explanation:

Draw two lines vertically down from side "A" to "B"...you now have three objects ... to triangles, and one rectangle the area of the rectangle is "AH"...now you have two triangles, that have area 1/2 base*height... the height is "H" and the base well it is (B-A)/2... so the area of the two triangles are (2)*(1/2)*((B-A)/2)* H The total area is AH + (2)*(1/2)*((B-A)/2)* H 2* 1/2 = 1 so now we have AH +   ((B-A)/2)* H to help see this let us write it as AH + H(B-A)/2 .. expand the right H AH + BH/2 - AH/2

you end up with : AH - AH/2 + AB/2 ...

AH - AH/2 =  AH/2

BH/2 = BH/2

final answer : AH/2 + BH/2

factor out the 1/2 and H 1/2 H (A+B)

d i think

step-by-step explanation: