Ineed on #7 and #8 i need it before monday

Because these are both right triangles, you can use the pythagorean theorem:

a² + b² = c²

a and b are sides while c is the hypotenuse.

for #7, you have two sides and you need the hypotenuse, so you'll set it up like so:

3² + 4² = c² ... solve for c, simplify exponents
9 + 16 = c² ... add
25 = c² ... square root both sides
√25 = c
c = 5

so your missing side for #7 is 5.

#8 follows the same process. you have one side and the hypotenuse:

a² + 15² = 17²
a² + 225 = 289
a² = 64
a = 8

your missing side for #8 is 8!!

Skew lines(segments) are lines(segments) in 3 dimensions that do not intersect the given segment and are not parallel to it.  ae, bf, eg, and fh are your skew segments.  i hope that : )