Find angle M and angle J of the isosceles trapezoid
1 answer:
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Answer:
BC ≈ 4.0
Step-by-step explanation:
∠ DCA = 180° - 70° = 110° ( adjacent angles )
∠ DAC = 180° - (30 + 110)° ← sum of angles in triangle
∠ DAC = 180° - 140° = 40°
Using the Sine rule in Δ ACD to find common side AC
=
( cross- multiply )
AC × sin40° = 15 × sin30° ( divide both sides by sin40° )
AC = ≈ 11.668
Using the cosine ratio in right triangle ABC
cos70° = =
=
( multiply both sides by 11.668 )
11.668 × cos70° = BC , then
BC ≈ 4.0 ( to the nearest tenth )
Set up the following equations:
x represents car A's speed, and y represents car B's speed.
We'll use elimination to solve this system of equations. Multiply the first equation by 7:
Combine both equations:
Divide both sides by 28 to get x by itself:
The speed of car A is 80 mph.
Since we now know the value of one of the variables, we can plug it into the first equation:
Subtract 160 from both sides.
Divide both sides by 2 to get y by itself:
The speed of car B is 60 mph.
x represents car A's speed, and y represents car B's speed.
We'll use elimination to solve this system of equations. Multiply the first equation by 7:
Combine both equations:
Divide both sides by 28 to get x by itself:
The speed of car A is 80 mph.
Since we now know the value of one of the variables, we can plug it into the first equation:
Subtract 160 from both sides.
Divide both sides by 2 to get y by itself:
The speed of car B is 60 mph.