A. definition of right angle
B. substitution property
C. definition of congruent angles
Answer:
7. A = 40.8 deg; B = 60.6 deg; C = 78.6 deg
8. A = 20.7 deg; B = 127.2 deg; C = 32.1 deg
Step-by-step explanation:
Law of Cosines

You know the lengths of the sides, so you know a, b, and c. You can use the law of cosines to find C, the measure of angle C.
Then you can use the law of cosines again for each of the other angles. An easier way to solve for angles A and B is, after solving for C with the law of cosines, solve for either A or B with the law of sines and solve for the last angle by the fact that the sum of the measures of the angles of a triangle is 180 deg.
7.
We use the law of cosines to find C.






Now we use the law of sines to find angle A.
Law of Sines

We know c and C. We can solve for a.


Cross multiply.





To find B, we use
m<A + m<B + m<C = 180
40.8 + m<B + 78.6 = 180
m<B = 60.6 deg
8.
I'll use the law of cosines 3 times here to solve for all the angles.
Law of Cosines



Find angle A:





Find angle B:





Find angle C:





Answer:
G. 
Step-by-step explanation:
Given that figure I and figure II are similar, it follows that the ratio of their corresponding side lengths are equal and the same.
Thus:

Therefore, the proportion that must be true is:
✔️
Answer:
D. 3,461
Step-by-step explanation:
There are 3520 yards in two miles and 3,461 yards is less than 3,520... meaning that he lives closer to the school.
3,461 < 3,520
This is a quadrilateral, so the sum of interior angle measures, like a rectangle or square ( who’s interior angle measures are4 x 90) —— is 360
So ...
E + 89 + 130 + 90 = 360
E + 309 = 360
- 309 - 309
E = 51 degrees