1. Given any triangle ABC with sides BC=a, AC=b and AB=c, the following are true :
i) the larger the angle, the larger the side in front of it, and the other way around as well. (Sine Law) Let a=20 in, then the largest angle is angle A.
ii) Given the measures of the sides of a triangle. Then the cosines of any of the angles can be found by the following formula:
a^{2}=b ^{2}+c ^{2}-2bc(cosA)
2.
20^{2}=9 ^{2}+13 ^{2}-2*9*13(cosA) 400=81+169-234(cosA) 150=-234(cosA) cosA=150/-234= -0.641
3. m(A) = Arccos(-0.641)≈130°,
4. Remark: We calculate Arccos with a scientific calculator or computer software unless it is one of the well known values, ex Arccos(0.5)=60°, Arccos(-0.5)=120° etc
Answer:
- 120
Step-by-step explanation:
call x is the number you want to find
- (3/4 )x + 3
= (2/3)x - 6 - (3/4)x + (7/2) = (2/3)x - (13/2)
- (3/4)x - (2/3)x = - (13 /2) - (7/2)
- (1/12)x = -10
- x = -10 / (1/12) = -120
Answer:
$9 I think
Step-by-step explanation:
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The system of equations that models the given situation is given as follows:
<h3>What is a system of equations?</h3>
A system of equations is when two or more variables are related, and equations are built to find the values of each variable.
In this problem, the variables are given as follows:
- Variable x: Number of single lawns cut.
- Variable y: Number of front and back lawns cut.
He had 25 customers, hence:
x + y = 25.
He charges $15 for a single lawn and $25 for a front and back lawn, and made a total of $475, hence:
15x + 25y = 475
More can be learned about a system of equations at brainly.com/question/24342899
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