Because in effect an isosceles triangle has been constructed and the base angles are always equal.
Only one which is a tangent to that circle.
63o. Join the points where the tangents touch the circle to its centre to form a quadrilateral (two meeting tangents and two radii). These angles are both 90o, summing to 180o. Thus the other two angles - the one at the centre of the circle and the one where the tangents meet - sum to 360o - 180o = 180o (they are supplementary). The centre angle is given as 117o (the minor arc), so the angle where the tangents met is 180o - 117o = 63o.
Always one for sure, and never more than one.
The angle between the two tangents is 20 degrees.
No. A chord is a straight line drawn between any two points on the circumference of a circle. The longest chord is when the points are on opposite sides of the centre of the circle (and passes through the centre of the circle). The straight line which joins the points on opposite sides of the centre (through the centre) is called the diameter of the circle. Therefore the longest chord possible is the diameter of the circle. A circle with a diameter of 15 in can have a chord with a maximum length of 15 in.
Two tangents can be drawn from a point outside a circle to the circle. The answer for other curves depends on the curve.
2
An infinite amount
The diameter (across the widest part) is the longest chord that can be drawn on a circle.
No tangent No tangent
Only one which is a tangent to that circle.
Any tangent must contain a point outside the circle. So the answer to the question, as stated, is infinitely many. However, if the question was how many tangents to a circle can be drawn from a point outside the circle, the answer is two.
63o. Join the points where the tangents touch the circle to its centre to form a quadrilateral (two meeting tangents and two radii). These angles are both 90o, summing to 180o. Thus the other two angles - the one at the centre of the circle and the one where the tangents meet - sum to 360o - 180o = 180o (they are supplementary). The centre angle is given as 117o (the minor arc), so the angle where the tangents met is 180o - 117o = 63o.
Always one for sure, and never more than one.
Chord.
A chord is a straight line drawn through a circle which divides the circle into two parts. The line can be drawn anywhere in the circle EXCEPT the center where it becomes the diameter.
The angle between the two tangents is 20 degrees.