in the ACD triangle picture above, if CBD = 45°, CAD = 30°, AB = 20, then BC =....

Answer:
(C)10(√3 +1)
Step-by-step explanation:
let x be DC then
from fig. tan45° = DC/BC
we get DC = BC
then we get AC = 20+x
tan 30° = DC /BC
(1/√3)= (x)/(20+x)
20= x(√3-1)
x= 20/(√3 -1)
rationalize we get
x = 20(√3 +1)÷(3-1)
x = 10(√3+1)
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