How do you write 8.91 x 10⁴ in standard form?

What is the maximum of the sinusoidal function

Use the method of cylindrical shells to find the volume v generated by rotating the region bounded by the given curves about y = 8.8y = x3, y = 0, x = 4use the method of cylindrical shells to find the volume v generated by rotating the region bounded by the given curves about y = 8.8y = x3, y = 0, x = 4

What is the measure of angle lkj ? round to the nearest whole degree