Answer:
d≈7.07
Step-by-step explanation:
Using the formulas
P=4a
d= \sqrt{2} a
Solving ford
d= \sqrt{2} P/4=2·20
/4≈7.07107
That's a <em>rhombus</em>. If it has one interior right angle, then
it's a special case of rhombus known as a "square".
B.
9 = 3 x 3
21 = 3 x 7
GCF = 3
3 x 3 + 3 x 7 = 9 + 21 = 30
