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A polygon has 20 diagonals how many sides does it have?
It is an octagon with 8 sides. Let n be the number of sides = number of vertices. Then each vertex can be connected to n-3 other vertices, giving n(n -3) connections. However, this counts each vertex pair connection twice, so there are: n(n - 3) / 2 diagonals. Thus if there are 20 diagonals: n(n - 3) / 2 = 20 n2 - 3n = 40 n2 - 3n - 40 = 0 (n + 5)(n - 8) = 0 so n = -5 or 8. As a polygon cannot have a negative number of sides, n = 8.
How many diagonals does a nine sided polygon?
For an n-sided polygon, the number of diagonals is 1+2+3+....+(n-4)+2(n-3). For a nine-sided polygon, there are 1+2+3+4+5+2(6)=27 diagonals.
How many sides of each face does a dodecahedron have?
A dodecahedron is a 12 side polyhedron. A regular dodecahedron has regular pentagons (5 sides) for each face.
9x plus 5 equals 4x plus 3?
9x + 5 = 4x + 3 Subtract 4x from both sides: 5x + 5 = 3 Subtract 5 from both sides: 5x = - 2 Divide both sides by 5: x = -2/5 or -0.4
How do you solve the equation -3x minus 5 equals -20?
Add 5 to both sides of the equation to get rid of the - 5. -3x - 5 + 5 = -20 + 5 Solve and simplify. -3x = -15 Divide both sides of the equation by -3. x = 5
What shape has 5 sides and 2 diagonals?
There is none. A 5 sided shape is a pentagon but that has 10 diagonals, not 2.
How many diagonals does a shape with 8 sides have?
The formula for determining the number of diagonals in a shape is n(n-3)/2 where n=vertices, (corners or intersections of geometric shapes). For an eight sided shape we replace n with 8. 8(8-3)/2 8(5)/2 (8x5)/2 40/2=20 An octagon contains 20 diagonals. For a further example we can determine the diagonals in a shape with 5 sides: 5(5-3)/2 5(2)/2 (5x2)/2 10/2=5 A Pentagon contains 5 diagonals.
What has 5 sides and 5 diagonals?
It is a 5 sided pentagon
How many diagonals in pentagon have?
It has 5 diagonals.Formula: number of distinct diagonals = n(n-3)/2where n is the number of sides (or vertices)number of diagonals in pentagon:= 5(5-3)/2= 5(2)/2= 10/2= 5Answer: There are 5 diagonals in pentagon.
An Octangon is a shape with how many sides?
it has 5 sides
How many sides will a shape with 5 vertices have?
5
How many sides will a shape 5 vertice have?
5
Which polygon has number of sides is equal to the number of diagonals?
The five sided Polygon has 5 diagonals
How many diagonals are in a 7 sided polygon?
A 4-sided polygon has 2 diagonals. A 5-sided polygon, 5. 6-sided, 9. By induction, an n-sided polygon has 'n*(n-3)/2' diagonals. "n" is how many sides a shape has. so, (7)*(7-3)/2 now we have, 7*4/2 so, 28/2 = 14 Therefore, a 7-sided polygon would have 14 diagonals.
What are the mathematical names of the first ten polygons and their properties?
All polygons have 3 or more sides having exterior angles that add up to 360 degrees and the first 10 can be classed as follows in order of their geometrical names, number of sides, sum of interior angles and number of diagonals:- 1 Triangle: 3 sides, 180 degrees and no diagonals 2 Quadrilateral: 4 sides, 360 degrees and 2 diagonals 3 Pentagon: 5 sides, 540 degrees and 5 diagonals 4 Hexagon: 6 sides, 720 degrees and 9 diagonals 5 Heptagon or Septagon: 7 sides, 900 degrees and 14 diagonals 6 Octagon: 8 sides, 1080 degrees and 20 diagonals 7 Nonagon: 9 sides, 1260 degrees and 27 diagonals 8 Decagon: 10 sides, 1440 degrees and 35 diagonals 9 Undecagon: 11 sides, 1620 degrees and 44 diagonals 10 Dodecagon: 12 sides, 1800 degrees and 54 diagonals Note that all polygons can be regular, irregular, congruent or similar
How many diagonals does a pentagon have have?
a pentagon has 5 diagonals i ur gud at maths...
How many side are on a pentagone?
a shape with 5 sides
