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anonymous
 5 years ago
Need help with triangle questions! Please HELP!
Find the Area of Triangle ABC.
1. angle b = 25º, a = 10 mm, and c = 15 mm.
2. angle a = 42º, b = 12 cm, and c = 13 cm.
3. angle c = 100º, a = 5 in., and b = 4 in.
4. angle c = 59º, a = 25 ft, and b = 18 ft.
anonymous
 5 years ago
Need help with triangle questions! Please HELP! Find the Area of Triangle ABC. 1. angle b = 25º, a = 10 mm, and c = 15 mm. 2. angle a = 42º, b = 12 cm, and c = 13 cm. 3. angle c = 100º, a = 5 in., and b = 4 in. 4. angle c = 59º, a = 25 ft, and b = 18 ft.

This Question is Closed

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0are of a triangle is \[\frac{1}{2} ab sin(\theta)\] where \[\theta\] is the measure of the angle between a and b. so these are straightforward i think. first one is \[\frac{1}{2} 10 \times 15 \times sin(25)=31.7\] rounded.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0i am assuming that when you say angle b you mean angle B. commonly lengths are denoted by small letters and the angles opposite them by capitals.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0it this the answer to number 1?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0yes if i used my calculator correctly.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0can you answer the other 3 please? I will give you a good answer for all

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0want me to write the next one or do you want to do it. just use the formula.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0you do next one I will do last 2 if I can

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0ok here goes: \[\frac{1}{2}\times 12 \times 13 \times sin(42)=52.19\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0i am just using a calculator. you need one to find the sine of whatever. just make sure it is in "degree" mode. you do one and i will check.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0ok I did 1/2*5*4*sin100 and got 5.063 is that right?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0no you area must be positive.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0i think maybe your calculator is in radian mode. let me check.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0hmmm ok I am using the Ti84 Plus calc and idk what i did wrong how do I change it?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0hit "mode" and you should see the option there.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0http://answers.yahoo.com/question/index?qid=20090312222055AA3FPqb

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0wow thanks I get it now!! Can I ask 2 more 1 for each next section then maybe I can understand it!???

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Find the remaining sides and angles in each triangle. 1. In Triangle ABC , angle M= 38º, a = 20 cm and c = 14 cm.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0i need to know (or rather you need to know) what angle is M? is it opposite a, b or c?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.02. in triangle DEF, d = 24 m, e = 21 m, and f = 25 m. I will try this one Angle m is B

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0yeah it say m Angle B=...

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0so in the first one you don't know the length of the side opposite angle M = 38 yes?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0yes that sounds right

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0because either you are supposed to use the law of sines which says \[\frac{sin(A)}{a}=\frac{sin(B)}{b}=\frac{sin(C)}{c}\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0or you are supposed to use the law of cosines which says \[a^2=b^2+c^22bc cos(A)\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0in order to use the first one (which is always easier) you need to know three out of 4 numbers in any one of those ratios. but it looks like in this case you do not. you only know two sides but not the length of the side opposite one of the angles. so you have to use the law of cosines yes?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0so we will have to use \[b^2=a^2+c^2 2ac cos(B)\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0btw this is easy to remember because it is just pythagoras. if you had a right angle it would be \[c^2=a^2+b^2\] but if it is not a right angle you have to adjust by \[2ab cos(C)\] ok here goes: \[b^2=20^2+14^22\times 20 \times 14 \times cos(38)=154.7\] rounded

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0so \[b=\sqrt{154.1}=12.4\] rounded

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0at least that is what my calculator told me

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0ok lol that makes since

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0of course you are not done because you have to find all the rest.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0would it make it easier if I gave you choices? CHoices: b = 12.4 cm2, A = 78.1º, C = 41.5º b = 9.8 cm2, A = 56.1º, C = 57.5º b = 12.4 cm2, A = 98.1º, C = 43.9º b = 12.4 cm2, A = 92.3º, C = 37.6º

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0not really. especially since we have only knocked out one answer.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0you still have to find A and C

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0but do not use the law of cosines again, because now you know the side opposite one of the angles. to find angle A use \[\frac{sin(A)}{a}=\frac{sin(B)}{b}\] or \[sin(A)=\frac{a sin(B)}{b}\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0\[sin(A) = \frac{20 sin(38)}{12.4} = .993\] i think

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0damn i am not getting any of your answers.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0ok but i am sure this is correct. we have the 12.4 for sure. now let us find angle C \[\frac{sin(C)}{c}=\frac{sin(B)}{b}\] \[sin(C) = \frac{sin(B)}{b}\] \[sin(C) = \frac{14 sin(38)}{12.4}\] \[C=sin^{1}(\frac{14 sin(38)}{12.4})\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0but don't forget that we rounded b = 12.4. maybe if we don't round we get a more exact answer.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0yes i get 43.9 if i don't round for b. weird that they would give b as 12.4 but then not round to find A or C.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0no that was C A you find by subracting: 180  38  43.9=98.1

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0wanna try the next one?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0sryy gotta go thanks for the help tho
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