Things that I knew before the video were that I knew what a center, radius, diameter, and a chord were. This is all that I knew about before watching the video.
Things that I learned about after watching the video were that I learned about what a secant and a tangent were. I also learned about the three different ways circles can intersect. They can intersect each other at two points, one point, or not at all. If they don’t intersect at all, they are called concentric circles. I also learned about common tangents. A common tangent is a line tangent to two or more circles. There are also tangent theorems. One is if m is tangent to circle Q at P, then m is perpendicular to line QP and vise versa (if m is perpendicular to line QP, then m is tangent to circle Q at P). You can use this to find out if there is a tangent to a circle and to find out the radius of a circle. Another tangent theorem is if line SR and line ST are tangent to circle P, then line SR is congruent to line ST. You can use this to find the value of X when you are given the length of ‘ST’ and ‘SR’. This is everything that I learned about after watching the video.
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I commented on Riley Eickert's and Leah S.'s blogs.
For your first question you have to use the pathgorean therom. You take 28 squared plus r squared equals (r+14) squared. Then after distributing you get 784+r squared equals r squared plus 28r+196. Then because you have r squared on each side you can cancel them out and then you would have 784=28r+196. Then you take 196 minus 784 to get 588=28r, then you divide by 28 to get r=21. For you second question you have to set of side equal to each other to get x squared plus 2=11. Then you minus the 2 over to the side of 11 to get 9 then you square each side to get x=3
ReplyDeleteI agree with what you have written. For your second question, you can use one of the tangent theorems to help. Because the two lines are tangent to the circle, you know that they or congruent, so then they are also equal. You can then put 11=2+x^2. Then you would minus to and get 9=x^2. Then when you square root 9 you get three but because when you multiply negative numbers, they become positive, it could be negative or positive 3 so it is both.
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