Find the Area $a = 30 \mathrm {~m} , \mathrm {~b} = 90 \mathrm {~m}$

Multiple Choice

Find the area.
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$a = 30 \mathrm {~m} , \mathrm {~b} = 90 \mathrm {~m}$

A) $1200 \mathrm {~m} ^ { 2 }$
B) $120 \mathrm {~m} ^ { 2 }$
C) $2700 \mathrm {~m} ^ { 2 }$
D) $5400 \mathrm {~m} ^ { 2 }$