Answer:
x=3cm
Explanation:
We have three figures.A triangle(8 by X+3).In it we have another triangle(4 by x)and a trapesium
thus that means the area of the trapesium+area of small triangle=area of big triangle.
1)Area=1/2lengthxwidth. =1/2×8×(x+3)
=4(x+3)
=4x+12cm³
2)Area=1/2lengthxwidth. =1/2×4×x
=2x
3)area=1/2(a+b)h
=1/2(x+3+x)×4
=1/2×4(2x+3). (area of trapesium)
=2(2x+3)
=4x+6cm³
thus:
2x+4x+6=4x+12 put like terms together
2x+4x-4x=12-6
2x=6 divide both sides by 2
x=3cm