Answer:
m∠A = 31
b = 13.3
Step-by-step explanation:
Answer:
Use Heron's formula; see below.
Step-by-step explanation:
Use Heron's formula.
Let the sides of the triangle have lengths a, b, and c.


Example:
A triangle has side lengths 3, 4, and 5 units.
Find the area of the triangle.








B, because to substitute for a variable you have to have an equation to substitute first.
Answer: $70 per year.
Step-by-step explanation:
Let's say that x is the number of years that has passed and y is how much the stamp is worth.
So we know that in zero years the stamp was worth $420 because that is the time Sheri gave her brother Sam the stamp. That could bring up the coordinates (0,420) .
Now we know that in 8 years it was worth $980 and that could be the coordinates (8,980)
To find the rate of change we need to find the different between the y value and divide it by the difference in the x values.
420 - 980 = -560
0-8 = -8
-560/-8 = 70
The rate of change is 70 which means that it grew by $70 every year.