360 degrees in a circle
360 degrees minus 90 degrees (the right angle of the square) = 270 degrees
270 degrees divided by 2 = 135 degrees
f = 135 degrees
Answer:
C. 18 cm
Step-by-step explanation:
The ratio of the sides of the triangle shown is 12 : 15 = 4 : 5. We know it is a right triangle, so we know the missing side length completes the ratio
3 : 4 : 5 = 9 : 12 : 15
Half of XY is 9 cm, so the length of the entire chord is 18 cm.
_____
The chord is tangent to the inner circle, so makes a 90° angle with the radius to that tangent point. This tells you that the triangle shown is a right triangle. It also tells you that the short radius bisects the chord. The Pythagorean theorem can be used to find the length of the side not shown (half the chord length).
The unknown side (a) can be found from ...
15² = 12² +a²
225 -144 = a² . . . . . . subtract 12²
81 = a² . . . . . . . . . . . simplify
9 = a . . . . . . . . . . . . . take the square root
The chord length is 2a, so is ...
2(9 cm) = 18 cm . . . . length of chord XY
Answer:
1. 8 + 13 = 13 + 8.
2. 6 + ( 12 + 4) = 6 + ( 4 + 12).
Step-by-step explanation:
Your line is wrong from the start. But for the equation:
