Given that ABCD is similar to WXYZ, solve for 'x'. Show all work and explain your method.

x=8

Step-by-step explanation:

Since the two parallelograms are similar, their corresponding sides should be proportionate. Therefore, we can set up a proportion to help us solve for x. That'll be AB/WX=AD/WZ, since those match up the corresponding sides.

4/18=6/4x-5

4(4x-5)=108

16x-20=108

16x=128

x=8

ending amount = beginning amount / (2^n)

where "n" = number of half-lives (or elapsed time / half-life)

ending amount = 50 mg / (2 ^10 / 5.3)

ending amount = 50 mg / (2 ^ 1.8867924528)

ending amount = 50 m / 3.6981210597

ending amount = 13.5203794557 mg

or about 13.5 mg remain

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