alleryStart learning →A square frame has outer side a+2 cm and inner side a cm, with a>0. What is its border area?
A2a + 2 cm²
B4a + 2 cm²
C4a + 4 cm²
D2a + 4 cm²
Answer & Solution
Correct answer: C. 4a + 4 cm²
Subtracting the inner square area gives (a + 2)² − a² = 4a + 4 square centimetres.
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