Ill mark if its correct. :) a, b,c, or d. answer quick please

Arectangular prism is 3 meters long, 6 meters wide, and has a height of 9 meters. what is its surface area?

which of the following sets of data would produce the largest value for an independent-measures t statistic? the two sample means are 10 and 20 with variances of 20 and 25 the two sample means are 10 and 20 with variances of 120 and 125 the two sample means are 10 and 12 with sample variances of 20 and 25 the two sample means are 10 and 12 with variances of 120 and 125

The distance of a chord from the centre of a circle is 12cm and the lenght of the chord is 10cm. find the radius of the circle