February 28, 2011
Warm Up 5-1
1. Find area, arc length, and perimeter of the sector
40o
10cm
20 o47'
2. Find x, y, and
x
5 ft
o
90
(exact if possible)
x
9ft
60
o
y
30o
8yd
6cm
x
y
February 28, 2011
Review..
How do you find a missing side in a right triangle when 2 sides are
known?
If it is either a 30-60-90 triangle, or a 45-45-90 triangle, how
many sides do we need in order to find missing ones?What are the
Exace Value Triangles?
If it is not exact value triangle, and we only have one side, we can
still find missing sides as long as it is a RIGHT TRIANGLE and we
have an angle in addition to the right angle.
What does SOHCAHTOA stand for?
We can even find missing angles if we know two sides in a right
triangle, but we must use inverse trig functions
o
What does 25 35'26'' mean, and how do we convert it to decimal?
February 28, 2011
Sometimes the hardest part of the problem is
understanding the wording and how to draw a
picture. For example:
Find the angle subtended at the circumference of a
circle of radius length 12cm by an arc which forms a
sector of area 120 sq cm
February 28, 2011
And sometimes you have to get creative:
Find how tall the hill is by making the following measurements
25o
[--100 ft--]
32o
February 28, 2011
You had a similar problem on #4-4 p. 277 4a where they asked you
to find x EXACTLY
x
o
30
|-----50-----|
45
o
February 28, 2011
#5-1 p. 312 1iii, 1vii, 3,5,9,14
To get a full stamp, you must have at least attempted
EVERY problem, and that means drawing a diagram! 14 is
good problem solving and you should be able to do it if you
draw the cone.
HW quiz tomorrow! Tomorrow we will go back to the PC
book for a while