Answer:
1. Perpendicular
2. Isosceles
3. Never
Step-by-step explanation:
1. AC ⊥ BD because diameter of a square are perpendicular bisector of each other.
2. In Δ AOB , By using pythagoras : AB² = OA² + OB² .......( 1 )
In Δ COB , By using pythagoras : BC² = OC² + OB² ..........( 2 )
But, OA = OC because both are radius of same circle
So, by using equations ( 1 ) and ( 2 ), We get AB = BC ≠ AC
⇒ ABC is a triangle having two equal sides so ABC is an isosceles triangle.
3. The side can never be equal to radius of circle because the side of the square will be chord for the circle and in a circle chord can never be equal to its radius
Solution:
Given:

To get sin 240 degrees:
240 degrees falls in the third quadrant.
In the third quadrant, only tangent is positive. Hence, sin 240 will be negative.

Using the trigonometric identity;

Hence,

To get cos 240 degrees:
240 degrees falls in the third quadrant.
In the third quadrant, only tangent is positive. Hence, cos 240 will be negative.

Using the trigonometric identity;

Hence,

To get tan 240 degrees:
240 degrees falls in the third quadrant.
In the third quadrant, only tangent is positive. Hence, tan 240 will be positive.

Using the trigonometric identity;

Hence,

To get cosec 240 degrees:

To get sec 240 degrees:

To get cot 240 degrees:
38.94 rounded to the nearest tenth. To know if we should round up or down, we look to the number in the hundredths place. If that number is 5 or greater, we round up. If the number is 4 or less, we round down
38.94
The number is 4, so we round down. 38.94 becomes 38.9
65.45 rounded to the nearest tenth. To know if we should round up or down, we look to the number in the hundredths place. If that number is 5 or greater, we round up. If the number is 4 or less, we round down.
65.43
The number is 3, so we round down. 65.43 becomes 65.4
38.9+65.4= 104.3
If you were to estimate 38.94+65.43, we round the number to numbers that we can easily calculate in our head. 38.94+65.43 becomes 40+65
40+65=105