Answer:
ABCD is a parallelogram.
Step-by-step explanation:
A parallelogram is a quadrilateral that has two parallel and equal pairs of opposite sides.
From the given diagram,
Given: AD = BC and AD || BC, then:
i. AB = DC (both pairs of opposite sides of a parallelogram are congruent)
ii. <ADC = < BCD and < DAB = < CBA
thus, AD || BC and AB || DC (both pairs of opposite sides of a parallelogram are parallel)
iii. < BAC = < DCA (alternate angle property)
iv. Join BD, line AC and BC are the diagonals of the quadrilateral which bisect each other. The two diagonals are at a right angle to each other.
v. <ADC + < BCD + < DAB + < CBA = 
(sum of angles in a quadrilateral equals 4 right angles)
Therefore, ABCD is a parallelogram.
Answer:
it might be the second one not sure
Answer:
d=2_f - 9h_f
Step-by-step explanation:
es la segunda opción
Answer:
Probably unequal ( B )
Step-by-step explanation:
<u>experimental group = 10</u>
using 85% ethanol gasoline
mean = 240 pounds per 100 miles
standard deviation = 20 pounds
<u>control group = 14 vehicles </u>
using regular gasoline
mean = 252 pounds per 100 miles
standard deviation = 15 pounds
comparing the sample variance of each group shows that they are probably unequal using the equation below
Variance for a sample set of data = ∑ ( x - X ) ^2 / n - 1
where n = number of events
X = mean value
x = value of events
