Answer:
The area of an octagon whose perimeter is 120 cm is 1086.4 
Step-by-step explanation:
An octagon is a polygon with eight sides. If the lengths of all the sides and the measurement of all the angles are equal, the octagon is called a regular octagon.
There is a predefined set of formulas for the calculation of perimeter, and area of a regular octagon.
The perimeter of an Octagon is given by
and the area of an Octagon is given by
We know that the perimeter is 120 cm, solving for side length (a) in the perimeter formula we get
Now, we calculate the area
7978 years
Step-by-step explanation:
A = A02^(-t/hl)
where hl = half-life.
Dividing both sides by A0 and taking the logarithm, we get
ln(A/A0) = -(t/hl)ln2
or solving for t,
t= -(hl)ln(A/A0)/ln2
note that A/A0 = 0.38
t = -(5715 yrs)[ln(0.38)/ln2]
= 7978 years
The value of the function f(x) = x² + 6x - 9 when x = -5 is -14.
<h3>What is an equation?</h3>
An equation is an expression that shows the relationship between two or more numbers and variables.
An independent variable is a variable that does not depends on other variable while a dependent variable is a variable that depends on other variable.
Given that:
f(x) = x² + 6x - 9
When x = -5:
f(-5) = (-5)² + 6(-5) - 9 = -14
The value of the function f(x) = x² + 6x - 9 when x = -5 is -14.
Find out more on equation at: brainly.com/question/2972832
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Answer:
TSA=115.5cm²
Step-by-step explanation:
T.S.A=3πr²
Given r=3.5cm
eq.
3×22/7×3.5×3.5
=3×22×0.5×3.5
=115.5cm²
