If it is known that the length of the side edge of the regular triangular prism abc-a1b2c3 is equal to the length of the side edge of the bottom, what is the sine value of the angle between Ab1 and acc1a1

If it is known that the length of the side edge of the regular triangular prism abc-a1b2c3 is equal to the length of the side edge of the bottom, what is the sine value of the angle between Ab1 and acc1a1

Take the midpoint D1 of a1c1 and connect BD1 and AD1,
In the regular triangular prism abc-a1b1c1, BD1 ⊥ c1a1,
Then, b1ad1 is the angle between Ab1 and acc1a1,
∵ the side edge length of the regular triangular prism abc-a1b1c1 is equal to the side length of the bottom surface,
∴ sin∠B1AD1=√6/4,