Question

Help theres a time limit​

Answer 1

C.
`= 36 √(7) {cm}^(2)`

Explanation:

`3 √(3) * 4 √(21) {cm}^(2)`

`12 √(63) {cm}^(2) = \sqrt{ {3}^(2) * 7 } \\ = \sqrt{ {3}^(2) } √(7) = 3 √(7)`

`12 * 3 √(7) {cm}^(2)`

`\boxed{\green{ = 36 √(7) {cm}^(2)}}`