Part a) If m VU= 80° and m ST= 40°, then ∠1 =
we know that
The measurement of the external angle is the semi-difference of the arcs it comprises.
so
![Angle (1)=\frac{1}{2}*(80\°-40\°)=20\°](/tpl/images/0495/2621/875b7.png)
therefore
the answer Part a) is
∠1 =![20\°](/tpl/images/0495/2621/c548f.png)
Part b) If m VU= 70° and m ST= 30°, then ∠2 =
we know that
The measure of the internal angle is the semi- sum of the arcs comprising it and its opposite.
so
![Angle (2)=\frac{1}{2}*(70\°+30\°)=50\°](/tpl/images/0495/2621/d5fa2.png)
the answer Part b) is
∠2 =![50\°](/tpl/images/0495/2621/f2b83.png)
Part c) If m VB= 60° and m BS = 30°, then ∠3 =
we know that
The measurement of the external angle is the semi-difference of the arcs it comprises.
so
![Angle (3)=\frac{1}{2}*(60\°-30\°)=15\°](/tpl/images/0495/2621/61ccc.png)
therefore
the answer Part c) is
∠3 =![15\°](/tpl/images/0495/2621/c0cd3.png)
Part d) If VS = 9, SP = 12 and UT = 4, then TP =
we know that
The Intersecting Secants Theorem states that when two secant lines intersect each other outside a circle, the products of their segments are equal.
so
![PT*PU=PS*PV](/tpl/images/0495/2621/fe6d2.png)
we have
![PS=12\ units\\PV=PS+VS=12+9=21\ units\\PU=PT+UT=PT+4](/tpl/images/0495/2621/6763a.png)
substitute
![PT*(PT+4)=12*21](/tpl/images/0495/2621/6c906.png)
![PT^{2} +4PT-252=0](/tpl/images/0495/2621/30264.png)
using a graphing tool------> to resolve the second order equation
see the attached figure
the solution is
![PT=14\ units](/tpl/images/0495/2621/1b093.png)
therefore
the answer Part d) is
![PT=14\ units](/tpl/images/0495/2621/1b093.png)
![Given: pb tangent pv, pu secants if m vu= 80° and m st= 40°, then ∠1 = if m vu= 70° and m st= 30°](/tpl/images/0495/2621/5a531.jpg)