High School

Raj tested his new flashlight by shining it on his bedroom wall. The beam of light can be described by the equation [tex]x^{2} + y^{2} - 2x - 4y - 31 = 0[/tex]. How many inches wide is the beam of light on the wall?

Answer :

Answer:

Diameter=12 inches

Step-by-step explanation:

Given:

x^{2}+y^{2}-2x-4y-31=0

Using completing the square

x^2 - 2x + 1 + y^2 - 4y + 4 = 31+1+4

(x-1)^2 + (y-2)^2 = 36

Rewrite in the form

(x-h)^2+(y-k)^2=r^2

We have,

(x-1)^2+(y-2)^2=6^2

radius = 6

Diameter =radius ×2

=6 × 2

diameter = 12 inches

Other Questions