Question 1206536
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The linear scale factor from EBT to SDA is 1/3 because 21/63 = 1/3.
The side lengths of SDA are 1/3 as long compared to the side lengths of EBT.


DA/BT = 1/3
(x+3)/(6x) = 1/3
3(x+3) = 6x*1
3x+9 = 6x
9 = 6x-3x
9 = 3x
x = 9/3
x = 3


BT = x+3 = 3+3 = <font color=red>6</font>
DA = 6x = 6*3 = <font color=red>18</font>
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