Can someone explain how you do this. i would really appreciate it.

Check the picture below.

now, let's recall that running a segment from a midpoint across to a midpoint in a triangle, creates a midsegment, and a midsegment which is parallel to the "base" of the triangle, is always half of that base.

now, noticing the picture on the top-left triangle, we know those points are midpoints, so those in red are midsegments and therefore half the base, to make it short

IC = HE/2 = 7

JB = IC/2 = 3.5

now onto the top-right triangle, which is the same thing just basing itself on its other end

CG = AH/2 = 10

DF = CG/2 = 5

now, let's go to the  picture on the bottom-center

we  know that DG = 4, and since D and G are midpoints, DG is the midsegment of CEH thus

CH = 2DG = 8

likewise, on the green triangle ACH, the midsegment IB is half of the base CH, we know CH = 8, so IB = 4.

0.02

step-by-step explanation:

time of 9 192 631 770 periods of the radiation corresponding to the transition between the 2 hyperfine levels of the ground state of the caesium 133 atom at 0 k (but other seconds are sometimes used in astronomy)

(b) 240

step-by-step explanation:

first, we use the pythagorean formula using the given side lengths to find x. then we use x to find the side lengths. then we add the side lengths to find the perimeter.

pythagorean theorem formula:

a^2 + b^2 = c^2

(x - 20)^2 + (x - 40)^2 = x^2

x^2 - 40x + 400 + x^2 - 80x + 1600 = x^2

x^2 -120x + 2000 = 0

(x - 100)(x - 20) = 0

x - 100 = 0 or x - 20 = 0

x = 100 or x = 20

we see that the solution x = 20 must be discarded because it will give a negative side length and a side length of 0. the only valid solution is x = 100.

perimeter = sum of the lengths of the sides

perimeter = x + x - 20 + x - 40

perimeter = 3x - 60

replace x with 100.

perimeter = 3(100) - 60

perimeter = 300 - 60

perimeter = 240