Identify two similar triangles in the figure, and explain why they are similar. then find ab.

Therefore,

ΔABD ~ ΔACB by Angle-Angle Similarity Postulate

AB is 8 unit.

Step-by-step explanation:

Given:

∠ABD ≅ ∠BCD

AD = 4

DC = 12   Therefore AC =AD + DC = 4 +12 =16

AC =16

To Find:

Similar Triangles

AB =?

Solution:

In  ΔABD  and ΔACB  

∠ABD ≅ ∠ACB      ……….{Given}

∠ A  ≅ ∠ A               .……..{Reflexive Property}

ΔABD ~  ΔACB  ….{By Angle-Angle Similarity Postulate}

If two triangles are similar then their sides are in proportion.  

Substituting the values we get

Therefore,

ΔABD ~ ΔACB by Angle-Angle Similarity Postulate

AB is 8 unit.

if you mean

then it's c. 8, -7/3

but if you mean

then it is