Is the square root of 21 is an irratoinal number true or false explain

Divide and round to the nearest hundredths place. 0.82 : 9

Solve the equation 3 (-a-3) - 2 (3a+3) = -78

Find the percent of the change from 145 to 85

If A and B are 6x5 matrices, and C is a 8 x 6 matrix, which of the following are defined? A. CT B. AC C. B+C D. A+B E. ABT F. CA

How do you calculate the area of a triangle using trigonometry?

Mrs. Barlow's math class took a test yesterday. Out of 80 students, 70% of them passed. How many of Mrs. Barlow's students passed the test?

What's the result of: (2/3) ³

Airline fares for a flight from Dallas to Austin are $30 for first class and $25 for the tourist class. If a fight had 52 passengers who paid a total of $1360, how many first class passengers were on the trip?

You have a recipe that requires 1/3 cup of sugar, but you only want to make a fourth of the recipe. How much sugar do you need to make this fraction of the recipe?

I just need clarification. If a rectangular prism has the dimensions of 10 by 4 by 6, The volume would be 240 in³ and the surface area would be 248 in² right?