Pls help with the question

Will give brainliest sum of arithmetic series (sigma notation) find the numerical answer to the summation given below. (image shown below)

The number of revolutions of two pulleys is inversely proportional to their diameters. if a 24-inch diameter pulley making 400 revolutions per minute is belted to an 8-inch diameter pulley, find the number of revolutions per minute of the smaller pulley.

The equation of a circle is (x - 3)2 + (y - 7)2 = 25. determine the length of the radius. 4 25 12.5 5 write the standard equation of the circle with center (2, 3) and a diameter of 12. (x - 2)2 + (y - 3)2 = 36 (x + 2)2 + (y + 3)2 = 12 (x - 2)2 + (y - 3)2 = 6 (x - 3)2 + (y - 2)2 = 36 the equation of a circle is (x + 3)2 + (y + 7)2 = 25. where is (3, 4) located in relation to the circle? on the circle in the interior of the circle in the exterior of the circle at the center of the circle