Question

Question #f5c34

Answer 1

`DC=30cm.`

Explanation:

Let `M and N` be the feet of `bot` from `A and B` on side `DC`, resp.

In the `Delta ADM, AD=12, /_AMD=90^@, and /_ADM=60^@`,

so, `/_MAD=30^@`. Therefore, side opp. to `/_MAD`=1/2 of the

Hypo., or, `DM=1/2(AD)=1/2(12)="6 cm"`.

Similarly, `NC="6 cm"`.

Finally, `DC=DM+MN+NC=DM+AB+NC=6+18+6=30cm.`