Trigonometry problem gives a wrong answer
1
$begingroup$
A. Find the BC.
Information: <) BAC = 65 (the base), AD = 10
I could not get it to work.
What I did is, I took ADB and then I divided 65 by 2 so BAD = 32.5.
Now I need to find BD so I did
tan (32.5) * 10 = 6.37 * 2 = 12.74
so BC = 12.74, but in the book the answer is 8.12, what did I do wrong?
trigonometry
edited Dec 24 '18 at 7:20
Glorfindel
3,42981830
asked Nov 6 '13 at 17:15
RoyRoy
414
$endgroup$
add a comment |
1
$begingroup$
A. Find the BC.
Information: <) BAC = 65 (the base), AD = 10
I could not get it to work.
What I did is, I took ADB and then I divided 65 by 2 so BAD = 32.5.
Now I need to find BD so I did
tan (32.5) * 10 = 6.37 * 2 = 12.74
so BC = 12.74, but in the book the answer is 8.12, what did I do wrong?
trigonometry
edited Dec 24 '18 at 7:20
Glorfindel
3,42981830
asked Nov 6 '13 at 17:15
RoyRoy
414
$endgroup$
$begingroup$
because you are assuming that AD is bisector, which is not given moreover AD is not perpendicular to BC, at least it is not given
$endgroup$
– newzad
Nov 6 '13 at 17:18
$begingroup$
I think you need another piece of information. So far you only have an angle and a side. Are $AE$ and $CE$ altitudes?
$endgroup$
– Rocket Man
Nov 6 '13 at 17:25
$begingroup$
What is $E$? Is the triangle isosceles? How is $D$ defined?
$endgroup$
– pi37
Nov 6 '13 at 17:36
$begingroup$
The length of AD to the base BC is 10 cm
$endgroup$
– Roy
Nov 6 '13 at 17:40
add a comment |
1
1
1
$begingroup$
A. Find the BC.
Information: <) BAC = 65 (the base), AD = 10
I could not get it to work.
What I did is, I took ADB and then I divided 65 by 2 so BAD = 32.5.
Now I need to find BD so I did
tan (32.5) * 10 = 6.37 * 2 = 12.74
so BC = 12.74, but in the book the answer is 8.12, what did I do wrong?
trigonometry
edited Dec 24 '18 at 7:20
Glorfindel
3,42981830
asked Nov 6 '13 at 17:15
RoyRoy
414
$endgroup$
A. Find the BC.
Information: <) BAC = 65 (the base), AD = 10
I could not get it to work.
What I did is, I took ADB and then I divided 65 by 2 so BAD = 32.5.
Now I need to find BD so I did
tan (32.5) * 10 = 6.37 * 2 = 12.74
so BC = 12.74, but in the book the answer is 8.12, what did I do wrong?
trigonometry
trigonometry
edited Dec 24 '18 at 7:20
Glorfindel
3,42981830
asked Nov 6 '13 at 17:15
RoyRoy
414
edited Dec 24 '18 at 7:20
Glorfindel
3,42981830
asked Nov 6 '13 at 17:15
RoyRoy
414
edited Dec 24 '18 at 7:20
Glorfindel
3,42981830
edited Dec 24 '18 at 7:20
Glorfindel
3,42981830
edited Dec 24 '18 at 7:20
Glorfindel
3,42981830
3,42981830
asked Nov 6 '13 at 17:15
RoyRoy
414
asked Nov 6 '13 at 17:15
RoyRoy
414
asked Nov 6 '13 at 17:15
RoyRoy
414
414
$begingroup$
because you are assuming that AD is bisector, which is not given moreover AD is not perpendicular to BC, at least it is not given
$endgroup$
– newzad
Nov 6 '13 at 17:18
$begingroup$
I think you need another piece of information. So far you only have an angle and a side. Are $AE$ and $CE$ altitudes?
$endgroup$
– Rocket Man
Nov 6 '13 at 17:25
$begingroup$
What is $E$? Is the triangle isosceles? How is $D$ defined?
$endgroup$
– pi37
Nov 6 '13 at 17:36
$begingroup$
The length of AD to the base BC is 10 cm
$endgroup$
– Roy
Nov 6 '13 at 17:40
add a comment |
$begingroup$
because you are assuming that AD is bisector, which is not given moreover AD is not perpendicular to BC, at least it is not given
$endgroup$
– newzad
Nov 6 '13 at 17:18
$begingroup$
I think you need another piece of information. So far you only have an angle and a side. Are $AE$ and $CE$ altitudes?
$endgroup$
– Rocket Man
Nov 6 '13 at 17:25
$begingroup$
What is $E$? Is the triangle isosceles? How is $D$ defined?
$endgroup$
– pi37
Nov 6 '13 at 17:36
$begingroup$
The length of AD to the base BC is 10 cm
$endgroup$
– Roy
Nov 6 '13 at 17:40
$begingroup$
because you are assuming that AD is bisector, which is not given moreover AD is not perpendicular to BC, at least it is not given
$endgroup$
– newzad
Nov 6 '13 at 17:18
$begingroup$
because you are assuming that AD is bisector, which is not given moreover AD is not perpendicular to BC, at least it is not given
$endgroup$
– newzad
Nov 6 '13 at 17:18
$begingroup$
I think you need another piece of information. So far you only have an angle and a side. Are $AE$ and $CE$ altitudes?
$endgroup$
– Rocket Man
Nov 6 '13 at 17:25
$begingroup$
I think you need another piece of information. So far you only have an angle and a side. Are $AE$ and $CE$ altitudes?
$endgroup$
– Rocket Man
Nov 6 '13 at 17:25
$begingroup$
What is $E$? Is the triangle isosceles? How is $D$ defined?
$endgroup$
– pi37
Nov 6 '13 at 17:36
$begingroup$
What is $E$? Is the triangle isosceles? How is $D$ defined?
$endgroup$
– pi37
Nov 6 '13 at 17:36
$begingroup$
The length of AD to the base BC is 10 cm
$endgroup$
– Roy
Nov 6 '13 at 17:40
$begingroup$
The length of AD to the base BC is 10 cm
$endgroup$
– Roy
Nov 6 '13 at 17:40
add a comment |
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$begingroup$
because you are assuming that AD is bisector, which is not given moreover AD is not perpendicular to BC, at least it is not given
$endgroup$
– newzad
Nov 6 '13 at 17:18
$begingroup$
I think you need another piece of information. So far you only have an angle and a side. Are $AE$ and $CE$ altitudes?
$endgroup$
– Rocket Man
Nov 6 '13 at 17:25
$begingroup$
What is $E$? Is the triangle isosceles? How is $D$ defined?
$endgroup$
– pi37
Nov 6 '13 at 17:36
$begingroup$
The length of AD to the base BC is 10 cm
$endgroup$
– Roy
Nov 6 '13 at 17:40