Option A: 4 is the length of PE
Step-by-step explanation:
Given that PA=6, PD=4, and BE=5
We need to determine the length of PE
The length of PE can be determined using the intersecting secant tangent theorem.
Applying the secant tangent theorem, we get,
![PA^2=(BE+PE)(PE)](https://img.qammunity.org/2021/formulas/mathematics/high-school/j97h2u3yg9tb472x0d1npagikoaogpkdzt.png)
Substituting the values of the PA and BE, we get,
![6^2=(5+PE)(PE)](https://img.qammunity.org/2021/formulas/mathematics/high-school/hpj1j8jaezbznf4fhw0mt3bwbugpejvnnf.png)
Simplifying, we get,
![36=5PE+PE^2](https://img.qammunity.org/2021/formulas/mathematics/high-school/ywchzlmpz8jv9tjbyeqyn7hv3nfbbsxbav.png)
Subtracting both sides of the equation by 36, we get,
![0=-36+5PE+PE^2](https://img.qammunity.org/2021/formulas/mathematics/high-school/g41ntdgmf9b9vxnm1n4hdualyn28zav13b.png)
Switch sides, we get,
![PE^2+5PE-36=0](https://img.qammunity.org/2021/formulas/mathematics/high-school/wb7lr7qznen2owor85ghus13cr2fd2jg3u.png)
Solving this equation, we get,
![(PE+9)(PE-4)=0](https://img.qammunity.org/2021/formulas/mathematics/high-school/xuvwm53ui6ki1sor6edlbk49n9r0gtxxb9.png)
Equating each term equal to zero, we get,
and
![PE-4=0](https://img.qammunity.org/2021/formulas/mathematics/high-school/z2a8bwv4iyp1vwt93ac8crwy3j2a45umad.png)
Simplifying, we get,
and
![PE=4](https://img.qammunity.org/2021/formulas/mathematics/high-school/fuuaj15p42zb47czzjtnocehxy9hp7rt5g.png)
The value of PE cannot be negative.
Thus, the length of PE is 4.
Hence, Option A is the correct answer.