Answer:
30 cm²
Step-by-step explanation:
The diagonal of a rectangle divides it into two congruent triangles.
Therefore, A = B + C.
If the ratio of A : B is 10 : 3 and A = B + C then:
- A = 10x
- B = 3x
- C = 10x - 3x = 7x
If C is greater than B by 12 cm² then:
Find x by equating the two expressions for C:
⇒ C = C
⇒ 7x = 3x + 12
⇒ 4x = 12
⇒ x = 3
Substitute the found value of x into the expression for A:
⇒ A = 10 × 3
⇒ A = 30 cm²
