Let x be the length of each side of the nonagon. We then split up the nonagon into 9 congruent, isosceles triangles, each with base = x and height = 12. Then the area of each triangle is 1/2 • x • 12 = 6x, so the total area of the nonagon will be 9 • 6x = 54x.
To find x, we can use some facts from geometry and trigonometry.
• In any polygon, the sum of the measures of the exterior angles is 360°. So each of these exterior angles will measure 360°/9 = 40°.
• Exterior angles are supplementary to the interior angles. So each interior angle will measure 180° - 40° = 140°.
• Each of the 9 triangles are isosceles with base angles measuring half the interior angles of the nonagon, 140°/2 = 70°.
• Cut the triangle in half along the labeled inradius of the nonagon, which has length 12. In the resulting right triangle, we have
tan(70°) = 12 / (x/2)
and solving for x gives
tan(70°) = 24/x
x = 24/tan(70°)
x = 24 cot(70°) ≈ 8.7
Then the total area of the nonagon is
54x = 54 • 24 cot(70°) ≈ 471.7
Answer:
First term = -41.
Common difference = -15.
Step-by-step explanation:
nth term: an = a1 + (n - 1)d where a = first term and d = the common difference.
-671 = a1 + (43 - 1)d
-806 = a1 +(52 - 1)d
-671 = a1 + 42d
-806 = a1 + 51d
Subtracting ( to eliminate a1):
-671 - (-806) = 42d - 51d
-9d = 135
d = -15
Substitute for d in the first equation:
-671 = a1 + 42*-15
-671 = a1 - 630
a1 = -671 + 630 = -41.
LA = perimeter of base x height
Use Pythagorean theorem to find the base
4^2 + 6^2 = 52
Sq root of 52 is 7.2111...
4+6+7.2 = 17.2
17.2 x 8
137.6 is your answer
I believe the answer is 57
Answer:
12
Step-by-step explanation:
0 + 12 = 12