A Comment "If i know the measures of angles C and B, I can find the measures of A and D" is TRUE
Explanation :
If we know angles C and B we can find angles A and D as,
As from figure we know
A+B = 180°
∴ A = 180° - B ... we know B so we get A
Also,
B+C+D = 180° ... as BCD is a triangle
∴ D = 180° - (B+C) ... we know B and C so we get D
Answer:
Step-by-step explanation:
Each purchase will be the sum of products of item price and number of items. The two purchases give rise to two equations.
__
<h3>equations</h3>The variables are defined in the problem statement. The two purchases are ...
11r +16m = 6.23
13r +7m = 6.41
__
<h3>solution</h3>A calculator offers a simple way to find the solutions to these equations. The attachments show the solution to be ...
The cost of ribbon is $0.45; the cost of a marker is $0.08.
__
The "cross-multiplication" method of solving these equations seems particularly useful when the coefficients are mutually prime. It starts with a rewrite to general form:
Then we define three "cross products":
Δ1 = (11)(7) -(13)(16) = -131
Δ2 = (16)(-6.41) -(7)(-623) = -58.95
Δ3 = (-6.23)(13) -(-6.41)(11) = -10.48
The solutions are ...
r = Δ2/Δ1 = -58.95/-131 = 0.45
m = Δ3/Δ1 = -10.48/-131 = 0.08
The cost of ribbon is $0.45; the cost of a marker is $0.08.
_____
For more about the cross-multiplication method you can read ...
