3. Perimeter = 2 ( W + L)
So we have
2 ( √13 + 7√13 )
2 (8√13) =
16√13 units
4. √20 + √45 - √5 =
{ The trick here, NSS, is to try to write each radical in terms of the last one}
√ [ 4 *5 ] + √ [ 9 * 5 ] - √5 =
√4 *√5 + √9 *√5 - √5 =
2√5 + 3√5 - √5 =
5√5 - 1√5 =
4√5
