Respuesta :

i dont understand you have everything there

answer: 13 in^2

setup:
let x=the unknown area
let h=the unknown height

(42+x)=11*h
(27+x)=8*h

so

h= (42+x)/11
h= (27+x)/8

so

(42+x)/11=(27+x)/8
8*42+8x=11*27+11x
8*42-11*27=3x
x=8*14-11*9
x=112-99
x=13