240,302 views
23 votes
23 votes
Find the value of x and the length of ST

Find the value of x and the length of ST-example-1
User Coryrwest
by
2.5k points

1 Answer

17 votes
17 votes
Answer:

x = 13

The length of ST is 78

Step-by-step explanation:

ST and SR are tangents

From the diagram

ST = 9x - 39

SR = 6x

Note that:

Two tangents drawn from the same point external to a circle are equal

That is, ST = SR

9x - 39 = 6x

9x - 6x = 39

3x = 39

x = 39/3

x = 13

ST = 9x - 39

Suubstitute x = 13

ST = 9(13) - 39

ST = 117 - 39

ST = 78

User Dat Chu
by
2.7k points