Round 8.21 to the nearest tenth
2 answers:
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Answer:
Step-by-step explanation:
Let
x ---> the number
we know that
The algebraic expression is equal to multiply the number by 4, add 5 and equal 8
so
Solve for x
subtract 5 both sides
Divide by 4 both sides
Answer:
A) The total length of each edging in her scale drawing would be 19.2 centimeters.
B) Square or rectangle
C) angle α= 53.13 degrees
angle β= 36.87 degrees
height= 32 inches
base= 24 inches
hypotenuse 40 inches.
Step-by-step explanation:
Part A:
If the roll edging is 96 inches long and the scale chosen is
5inches = 1 cm
96inches /5= 19.2cm
The total length of each edging in her scale drawing would be 19.2 centimeters.
Part B:
The quadrilaterals such rectangle square right trapezoid have a pair of 90 degrees angles.
If we choose a square shape then all sides must be equal. And we have a length of 19.2 centimeters.
Dividing 19.2 by 4 gives 4.8 cm for each side.
Figure A shows a square and has 4 sides equal and 4 right angles.
If we choose a rectangle shape then 2 sides must be equal. We have a length of 19.2 centimeters.
Suppose the length is 2 times more than the width
which will give the dimensions as
2*2 x+ 2x= 6x ( length and width denoted by x)
Dividing 19.2 by 6 gives 3.2 cm for each width and 6.4 for the lengths.
Figure B shows a rectangle and has 2 sides equal and 4 right angles.
It depends on which quadrilateral you wish to choose.
Part C:
Using Pythagorus theorem if the base and altitude are given then the hypotenuse can be found out using the following formula.
c²= a² +b²
c²= 6.4² +4.8²
c²= 40.96+23.04= 64
c= √64 = 8
The third side must be equal to 8 centimeters.
Using the formula
Cos α= base / hypotenuse
Cos α=4.8/8
α= Cos (inverse) 4.8/8
α= Cos (inverse) 0.6
α= 53.13 degrees
So angle α= 53.13 degrees
All the angles in the triangle must be 180 degrees.
α + β + 90°= 180°
And angle β= 180-90-53.13= 36.869= 36.87 degrees
The actual dimensions of this triangle are
height= a= 6.4* 5= 32 inches
base= b= 4.8*5= 24 inches
hypotenuse= 8*5= 40 inches.
