How do you do the work for 4-4 study guide and intervention parallel and perpendicular lines
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<span>In triangle XYZ,
angle X=46 degrees,
XZ = 10 units and
YZ=8 units.
We will find the length of XY using cosine rule:
According to cosine rule:
a² = b² + c² - 2bc cosA (the figure is attached)
Here, A = 46 degree.
a = 8 units.
b <span>= ?
</span>c = 10 units.
</span>⇒ b² = c² - a² -2bc cosA
⇒ b² = 100 - 64 - 160*cos(46)
⇒ b² = 100 - 64 - 160*0.69
⇒ b² = 100 - 64 - 110.4
⇒ b² = 100 - 64 - 110.4
⇒ b² = 74.4
or b = 8.62 units.
or b = 8 untis approximately.
angle X=46 degrees,
XZ = 10 units and
YZ=8 units.
We will find the length of XY using cosine rule:
According to cosine rule:
a² = b² + c² - 2bc cosA (the figure is attached)
Here, A = 46 degree.
a = 8 units.
b <span>= ?
</span>c = 10 units.
</span>⇒ b² = c² - a² -2bc cosA
⇒ b² = 100 - 64 - 160*cos(46)
⇒ b² = 100 - 64 - 160*0.69
⇒ b² = 100 - 64 - 110.4
⇒ b² = 100 - 64 - 110.4
⇒ b² = 74.4
or b = 8.62 units.
or b = 8 untis approximately.
Normal-travel DATA:
distance = 240 km
rate = x km/h
time = d/r
= 240/x hrs
_______________________
Bad weather DATA:
distance = 240 km
rate = (x-20) km/h
time = 240/(x-20) hrs
______________________
Bad time - normal time = 2 hrs
240/(x-20) - 240/x = 2
120/(x-20) - 120/x = 1
120x -120(x-20) = x(x-20)
20 = x^2 -20x
x^2 - 20x - 20 = 0
x = [20 +- sqrt(20^2 - 4*1*-20)]/2
x = [20 +- sqrt(480)]/2
x = [20 +- 4sqrt(30)]/2
x = 10 +- 2sqrt(30)