Answer:

Step-by-step explanation:
we know that
Heron's Formula is a method for calculating the area of a triangle when you know the lengths of all three sides.
so

where
a, b and c are the length sides of triangle
s is the semi-perimeter of triangle
we have

<em>Find the semi-perimeter s
</em>
s=
Find the area of triangle



simplify

Answer:
Distance between the points A and B is 15.52 units.
Step-by-step explanation:
It has been given in the question that an airplane flies along a straight line from City A to City B.
Map has been laid out in the (x, y) coordinate plane and the coordinates of these cities are A(20, 14) and B(5, 10).
Distance between two points A'(x, y) and B'(x', y') is represented by the formula,
d = 
So we plug in the values of (x, y) and (x', y') in the formula,
d = 
d = 
d = 
d = 15.52
Therefore, distance between the points A and B is 15.52 units.
Answer:
Let the angle=x
So the other angle will be = y
X-28 +y=90
L(1, -4)=(xL, yL)→xL=1, yL=-4
M(3, -2)=(xM, yM)→xM=3, yM=-2
Slope of side LM: m LM = (yM-yL) / (xM-xL)
m LM = ( -2 - (-4) ) / (3-1)
m LM = ( -2+4) / (2)
m LM = (2) / (2)
m LM = 1
The quadrilateral is the rectangle KLMN
The oposite sides are: LM with NK, and KL with NK
In a rectangle the opposite sides are parallel, and parallel lines have the same slope, then:
Slope of side LM = m LM = 1 = m NK = Slope of side NK
Slope of side NK = m NK = 1
Slope of side KL = m KL = m MN = Slope of side MN
The sides KL and LM (consecutive sides) are perpendicular (form an angle of 90°), then the product of their slopes is equal to -1:
(m KL) (m LM) = -1
Replacing m LM = 1
(m KL) (1) = -1
m KL = -1 = m MN
Answer:
Slope of side LM =1
Slope of side NK =1
Slope of side KL = -1
Slope of side MN = -1