Round to the nearest 10th ? Triangles?

Question

So I have two right triangles backed up to each other with the right angles touching. There is a dotted line down the middle


One triangle has the sides 7m and x

The other triangle has the sides 7m and x

With the middle line that they both share being 3m

Here is the word problem associated with these numbers


A homeowner wishes to insulate her attic with fiberglass insulation toconserve energy. The insulation comes in 40-cm wide rolls that are cut to fit betweenthe rafters in the attic.

if the roof is 7 m from peak to eave and the attic space is 3 m high athe peak, how long does each o the pieces of insulation need to be?

Answer 1

a^2 + b^2 = c^2
3^2 + b^2 = 7^2
9 + 40 = 49
b = 12.64911064
if she is insulating the ceiling of the attic then the pieces are
14m long - eave to peak to eave
if she is insulating the floor of the attic then the pieces are
b x 2
or 25.29822128m long
rounded to the nearest 10th - 25.3m long

Answer 2

use the rght triangle formula - something like a^2 + b^2 = c^2

substitute the numbers and you'll get the third side. good luck