91Ó°ÊÓ

The diagram below shows tangent lines and circles. Find $PD$.

For each exercise draw a circle and inscribe the polygon in the circle.

a. Rectangle.

What name is given to point of $⊙o$.

Find the measure of central $∠1.$

$\stackrel{¯}{RS}$ and $\stackrel{¯}{TU}$are common internal tangents to the circles. If $RZ=4·7$ and $ZU=7·3$, Find $RS$ and $TU$.

In exercises $2-7$ find the measure of the arc.

$\stackrel{Áåœ}{CDA}$

Name the line tangent to sphere.

For each exercise draw a circle and inscribe the polygon in the circle.

b. A trapezoid.

In exercises $2-7$ find the measure of the arc.

$\stackrel{Áåœ}{CDB}$

$\left(a\right).$What do you think is true of common external tangents $\stackrel{¯}{AB}$and $\stackrel{¯}{CD}$$?$prove it.

$\left(b\right).$Will your results in part $\left(a\right)$be true if the circles are congruent$?$