Given:
The diagram shows two right-angled triangles OAB and OCD.
To find:
The length of BD.
Solution:
Let the length of BD is x.
In triangle OAB and OCD,
(Common angle)
(Right angle)
(By AA property of similarity)
We know that, the corresponding sides of similar triangles are proportional. So,
![(AB)/(CD)=(OB)/(OD)](https://img.qammunity.org/2022/formulas/mathematics/high-school/sbwbkw1puqo2o4s9xqxsx6w7tbpdtaek4k.png)
![(4)/(7)=(14)/(14+x)](https://img.qammunity.org/2022/formulas/mathematics/high-school/bhppwtb51p9xefqzohiu7v3408d809q0xa.png)
![4(14+x)=14(7)](https://img.qammunity.org/2022/formulas/mathematics/high-school/xmvbhw4eldkj34dp7cavhg54o455g91qux.png)
![56+4x=98](https://img.qammunity.org/2022/formulas/mathematics/high-school/zu4b0blz5t5oqpgg6376ub9vdhhadzaiiy.png)
Subtracting 56 from both sides, we get
![4x=98-56](https://img.qammunity.org/2022/formulas/mathematics/high-school/15ufxhh1r6244mua0c2zdm36q39iktva0d.png)
![4x=42](https://img.qammunity.org/2022/formulas/mathematics/high-school/5e4rwhdxzq0xnf1j5yag2fl69373pgribs.png)
![x=(42)/(4)](https://img.qammunity.org/2022/formulas/mathematics/high-school/fs82x9qqf45bommuyqr55zin11v4mflt2p.png)
![x=10.5](https://img.qammunity.org/2022/formulas/mathematics/high-school/11z8uhehxwpyv27xelwxnja5fv3c4ixun9.png)
Therefore, the length of BD is 10.5 cm.