2-17-2010+-+SIMILARITY+PROBLEMS+FROM+CLASS

OK, HERE ARE THE THREE PROBLEMS FROM CLASS.... Rules: ~Do one step only ~TALK - explain ~ write your name in after each line you write. ~ Draw pictures- they help!!! ~ If the two classes can get them ALL done by midnight TONIGHT, you get donuts in the morning! (And unbelievable knowledge of applications of similar polygons!)

1. **Use radicals and fractions, NO decimals.**

c^2=85 c=radical 85 (justyna)
 * First, you have to find the length of AC. So, it's 6^2+7^2=C^2

Agnes, didn't you have something here???? Where did it go? ~ Mrs. Bujdei set a proportion 6/7=(radical85/2)/X x=538/100 DE (agnieszka) now =) ?? **Better. But you're wrong :( Someone needs to check your work.**
 * AD and DC are congruent because DE is a perpendicular bisector so AD and DC = radical 85/2 (rebecca)
 * Triangle DEC=24in.(Harsh) HOW DID YOU GET FROM AD = DC = RADICAL 85/2 TO DEC = 24??? ??? missing steps. ~ Mrs. Bujdei

2. Triangle ABC is a right triangle with hypotenuse AC and altitude BD. If BC = 4 and AD = 9, then what is the length of DC ? (Use fractions and radicals, NO decimals).

Set a proporton small triangle to the big one. __4==9+x__ x==4 16=x2+9x = x2+9x+16 use quad. formula and it equals to - 9 square root of ** **+or-** ** 145 divided by 2 (Kamil.k**)
 * Ms. Bujdei this problem is the same as we had in Math Team

Kamil, the point was for people to work together! Oy. I know it was the same one :) I got it from there! I might erase it.... let others try! you did two of them by yourself. Or maybe I'll just add more problems.....

3. My dad was going to cut down a dead tree in our yard one day, but he was afraid it might hit some nearby power lines. He knew that if the tree were over 45 feet tall, the tree would hit the power lines. He stood 30 feet from the base of the tree and held a ruler 6 inches in front of his eye. He lined the bottom of the ruler up with the base of the tree, and saw that the top of the tree lined up with a point 8 inches high on the ruler. He then knew he could safely cut the tree down. How did he know? __6 =30__ 8 =x 8x30=240 240/6= 40feet so it will not hit the power lines because it will have 5 feet of clearance. Kamil.k. ~NICE!!! Good job Kamil :) ~ Mrs. Bujdei
 * Set a proportion -first by him then the tree which equals

4. Ok, you COULD cheat on this one, but don't. Just for your own mathematical knowledge. Find x and y. Hint- you need to expand the triangle.

1. I would set up pythagorean theorem: x^2+y^2=10^2. (Rachel)(my bad that it's past 12) 2. I made it into a triangle and it turns out to be an equilateral triangle. Wheee~ So 2y= 10 and y= 5. Then, you go to the pythagorean theorem. x^2 + 25 = 100. x^2= 75. x= 5 square root of 3. (Joyce) **

PART B) yahoo rachel and joyce!! :) Good job. Now let's expand on that..... Say I give you another 30-60-90 triangle with one leg measure of 5. Find the length of the other leg and the hypotenuse.

PART C) How can you find x and y here? More expansion required? Explain.

What about if the hypotenuse is 16? What are the lengths of the legs? Explain.