Answer:
value of a.b = -4
Step-by-step explanation:
We need to find a.b
a= 4i-4j
b = 4i+5j
We know that i.i =1, j.j=1, i.j =0 and j.i=0
a.b = (4i-4j).(4i+5j)
a.b = 4i(4i+5j)-4j(4i+5j)
a.b = 16i.i +20i.j-16j.i-20j.j
a.b = 16(1) +20(0)-16(0)-20(1)
a.b = 16 +0-0-20
a.b = 16-20
a.b =-4
So, value of a.b = -4
Answer:50 feet
142+482=502
196+2304=2500
Step-by-step explanation:
Answer:
1,164 in²
Step-by-step explanation:
the area of 1 sofa cushion =
2× ( 10×11 + 10×4 + 11×4)
= 2 × (110+40+44)
= 2×(194)
= 388 in²
the fabrics she needs to cover 3 sofa cushions =
3 × 388 = 1,164 in²
P(7,6), Q(1,6), R(4,2)
We have PQ parallel to the x axis. We'll call that the base,
b = 7 - 1 = 6
The altitude is then the y difference h = 6 - 2 = 4
The area is 
Answer: 12 square units
In general we can use the shoelace formula for the area of any polygon given coordinates. We write the points like this:
(7,6), (1,6), (4,2)
(1,6), (4,2), (7,6)
The area is then half the absolute value of the sum of the cross products:
The first ratio is 1:4 so if x is 6 then 6x4 is 24 your answer is 24.
