A=8
Explanation: a+b=12 a-b=4
^^^^^^^ ^^^^^^
8+4=12 8-4=4
A=8
1.253
Is the answer to ur question
The answer will be calculated by Pythagoras theorem here -
In order to find b1 from your formula stated we need to do few calculations
A=hb1+hb2, as you wee I multiply h with both bases( b1 and b2)
I will subtract hb2 from both sides
hb1=A-hb2
now I will divide my new expression by h
b1=(A-hb2)/h