In the figure, ABCD is a trapezoid with legs AB and CD.
Join AC and BD.
For the triangle CAD, from the vertex C, draw an altitude CE and for the triangle ABD, from the vertex B, draw an altitude BF.
Clearly, CE = BF = h (say) --- (1)
Note that the base of the triangles CAD and ABD are the same and is AD.
It is given that ar(CAD) =
.
Now, ar(ABD) = 
=
from (1)
= ar(CAD)
=
.
Hence, area of Δ ABD =
..
Answer: B
Step-by-step explanation:
Answer:
x = - 2
y = 6
Step-by-step explanation:
The best way to do this is to put - 3x in for y in the second equation.
4x - 2(-3x) = - 20 Watch the signs. You have 2 minus signs.
4x - - 6x = -20 Change - - 6x to 6x
4x + 6x = - 20 Add
10x = - 20 Divide by 10
x = -20/10
x = - 2
============================
Find y
y = - 3x
y = -3 * -2
y = 6
Answer:
T = 4.541
Step-by-step explanation:
We don't have the standard deviation for the population, so we use the t-distribution.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 4 - 1 = 3
98% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 3 degrees of freedom(y-axis) and a confidence level of
. So we have T = 4.541