Answer:
A is the answer
12 in
first substitute the variables
then 78=1/2h(5 + 8)
this makes it an equation
add similar terms which equals to
78=1/2xhx13
then divide both sides by 13
6=1/2xh
lastly divide both sides by 1/2
12=h
Step-by-step explanation:
proof
A=1/2x12(5 + 8) then
A=1/2x12x13 then
A=6x13 then
A= 78in^2
