•*Ok first let me show you the formula for the Area of the trapezoid.
A=a+b/2 h.(I will be using the letter x for the multiplication sign)
*And here is the formula to find the height of a trapezoid
h=2 x A/a+b (2 times the Area over base "a" plus base "b")
*We need to plug in the numbers: h = 2 x 136.5/6+15
*Next, we add the two bases to get 21: 6+15=21 (h=2 x 136.5)
*Then, divide the total of the two bases (21) from the area to get 6.5: 136.5/21-6.5
*Finally we multiply 2 by 6.5: 2 x 6.5= 13
The height if this trapezoid is 13.
Hope this helps you ☺
Since it has a half life of 60 days, this means that every 60 days it multiplies by 0.5. Since it asks for 300 days, your equation is 500*(0.5)^5, which is 15.625 mg left after 300 days.
I mean it should be 7 cause 2 angles are congruent.