In the given diagram, PS and PT are the tangents to the circle. SQ || PT and ∠SPT = 80°. The value of ∠QST is :

1. 140°

2. 90°

3. 80°

4. 50°

In the given diagram, ∆ABC ∼ ∆PQR. If AD and PS are bisectors of ∠BAC and ∠QPR respectively then:

1. ∆ABC ∼ ∆PQS

2. ∆ABD ∼ ∆PQS

3. ∆ABD ∼ ∆PSR

4. ∆ABC ∼ ∆PSR