Question

Can someone teach me how to do this because the online class i take doesn't really teach us the way i learn stuff like i need a formula not how they got the answer and no formula anyways help

x =

1
3
7

Answer 1

If what you are doing here is trying to get the value of x then:

Those two lines passing through the circle are secants.

Now, a formula I was taught in class is:

(outside)(whole) = (outside)(whole)

**1 SEGMENT'S VALUES PER SIDE** **DO NOT MIX**

"Outside" represents the value of the segment which is found outside of the circle.

The "whole" would be the outside segment plus the inside segment.

Thus, the formula would be:

(4)(9+4) = (x)(x + 12)

Next, you would simplify by adding, multiplying, and doing the distributive property:

(4)(13) = (x)(x + 12)

52 = x² + 12x

In this case, you would have to use the quadratic formula, while at other times, you could simply move around the terms and get the square root of a number.

Set the equation to zero:

x² + 12x - 52 = 0

Next plug-in the values

(-b (+ or -)√b² - 4 (a)(c) )/ (2)(a)

(-(12) (+ or - )√12² - 4(1)(-52)) / (2)(1)

(-12 (+ or -) √144 + 208) / 2

(-12 (+ or -) √352) / 2

Now, the square root of 352 would be approximate, since 352 is not a perfect square.

352 is approximately 18.7616630393 or, when rounded to the nearest hundredth, 18.76.

So.....

(-12 (+ or -) 18.76) / 2

Solve for both the + and the -

(-12 + 18.76) /2 = (approximately) 3.38 = x

(-12 - 18.76)/2 = (approximately) -15.38 = x

Therefore, x would be equal to 3.