Section 2.3 - significant figures and solving right triangles
Definition: The number of significant digits (or figures) in a number is found by counting all the digits from left to right beginning with the first nonzero digit on the left. When no decimal point is present, trailing zeros are not considered significant.
Significant figures
2 significant figures ­­ nearest degree
3 significant figures ­­ nearest 10' or 0.1o
4 significant figures ­­ nearest 1' or 0.01o
Find the number of significant figures in each of the following:
0.02
1.020
30
500
5001
40.
4.5
21.0
Significant figures
2 significant figures ­­ nearest degree
3 significant figures ­­ nearest 10' or 0.1o
4 significant figures ­­ nearest 1' or 0.01o
Find the number of significant figures in each of the following:
0.02 1
1.020 4
30
500 1
1
2
5001 4
40.
2
4.5
21.0 3
Solving a right triangle means to find any missing side or angle. Keeping in mind significant figures, let's solve the following triangle.
How many significant figures should we use?
B
o
B= 9.5 , a = 5.43 mi.
a
c
A =
a = 5.43 mi
B = 9.5o
b =
C = c =
A
b
C
Solve for all the missing parts of the following right triangles. Watch your significant figures and round at the end.
1.
B
b = 377.3", c= 588.5"
c
A
2.
B = 53o 30', b = 725 mm
3.
A = 42o, c = 89.0 ft
a
b
C
Solve for all the missing parts of the following right triangles. Watch your significant figures. C = 90o
1.
b = 377.3", c= 588.5"
B
a = 451.6", A = 50.12o
B = 39.88o
c
A
2.
B = 53o 30', b = 725 mm
3.
A = 42o, c = 89.70 ft
a = 536 mm
c = 902 mm
a = 60 ft
b = 67 ft
A = 36o 30'
B = 48o
a
b
C
C
r
If AD is tangent to the circle and C is its center, what is the measure of CDA?
B
x
r
D
1.
2. If A = 31o and r = 12, find x.
If C = 26o and x = 2.1, find r.
A
C
r
If AD is tangent to the circle and C is its center, what is the measure of CDA?
B
x
r
A
D
1.
If A = 31o and r = 12, find x.
x = 11
2. If C = 26o and x = 2.1, find r.
r = 19
As time permits...
work together to solve Homework Problem #52.