90 degree triangle. C=90 deg, A = 40 deg, base line of a=15cm. whats "b" and how... do you know any good math websites... Thanks Britt
2006-11-19 11:07:08 · 9 answers · asked by Britton J 2 in Science & Mathematics ➔ Mathematics
I don't know any good math websites but I do know how to solve this. b would be the side adjacent to the 40 degree angle and a is the side opposite it.
Tangent = opposite leg/adjacent leg so
tan 40 = 15/b
b tan 40 = 15
b = 15 / tan 40
2006-11-19 11:12:43 · answer #1 · answered by hayharbr 7 · 0⤊ 0⤋
Hi basically to find the solution you will have to use the Sine Rule
it says that (sinA) / (a) = (sinB) / (b)
so if you draw a triangle you will calculate one angle to be 50 degrees becuase triangles angles add upto 180 degrees. so 180 - 90 - 40 = 50
Now:
A is the angle at A which is 40 degrees.
B will be the angle at B which is 50 degrees
a is the length of the opposite egde of the triangle from angle A the same principal with B.
Hence a = 15 and b = ?
so plug into the equation of Sine Rule:
sin(40) / 15 = sin (50) / b
cross multiply to get: bsin(40) = 15sin(50)
Hence bring the sin(40) to the otherside
b = 15sin(50) / sin(40)
your answer will be (11.49) / (0.64) = 17.95
I also know a website which is excellent for learning mathematics, http://www.mathsnet.net/
I hope this helps.
2006-11-19 11:23:21 · answer #2 · answered by C.B 1 · 0⤊ 0⤋
Strategy:
Draw the triangle.
A = 40, C = 90 , B = 50 (angles add to 180)
use the trig identities
sin (A)/a= sin (B)/b and solve for b
Good luck.
2006-11-19 11:11:49 · answer #3 · answered by alrivera_1 4 · 0⤊ 0⤋
SohCahToa (ask your teacher). Assuming the 15cm side is opposite the 40° angle, 15/b = tan 40°. So b = 15/tan 40 = 15/.8391 = 17.88 cm.
For good math website see the links.
2006-11-19 11:18:57 · answer #4 · answered by Philo 7 · 0⤊ 0⤋
Start of by sketching a diagram and filling in all the info you know, from this you can work out what info you need to find. In your case, your looking to calculate the hypotenuse (long side, opposite the 90 degree angle), and your given the adjacent side and one angle.
The formula you need is
Cos A = Adjacent / Hypotenuse
Therefore
Cos 40 = 15 / b
Therefore
b = 15 * (cos40)
b = 11.491 (to 3 d.p.)
2006-11-19 11:11:17 · answer #5 · answered by hardhouse_boy 2 · 0⤊ 0⤋
well, the other angle will be 50 deg...and you can do the tan of 40 or 50 and use 15cm...its been a while but im sure thats right....
2006-11-19 11:09:54 · answer #6 · answered by Michelle D 2 · 0⤊ 0⤋
First of all, you know the angle A and side a. You know that c is a 90triangle.
You could use tanx...
tan(a) = a/b [ this be opposite over adjacent]
tan 40 = 15 / b
btan40 = 15
b = 15 / tan 40
2006-11-19 11:10:59 · answer #7 · answered by xchipowers 2 · 0⤊ 0⤋
b=a tan50. =15tan50
angle B=90-40
2006-11-19 11:11:04 · answer #8 · answered by Anonymous · 0⤊ 0⤋
utilising regulations of logs, log_7(36/x) = log_7(4) 36/x = 4 x = 9 utilising a similar equating technique on the subsequent question, 3x + 10 = x^2 x^2 - 3x -10 = 0 (x+2)(x-5) = 0 x = -2, x = 5.
2016-10-22 09:24:58 · answer #9 · answered by ? 4 · 0⤊ 0⤋