Find the volume of the cuboid in the form $a\sqrt{b} \text{ cm}^3$, where $a, b \in \mathbb{N}$. - Leaving Cert Mathematics - Question 3(a) - 2021
Question 3(a)
Find the volume of the cuboid in the form $a\sqrt{b} \text{ cm}^3$, where $a, b \in \mathbb{N}$.
Worked Solution & Example Answer:Find the volume of the cuboid in the form $a\sqrt{b} \text{ cm}^3$, where $a, b \in \mathbb{N}$. - Leaving Cert Mathematics - Question 3(a) - 2021
Step 1
Identify the relationships between dimensions
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Answer
The cuboid has dimensions x, y, and z cm. We can use the areas given to establish relationships:
From the area of the face with dimensions x and z: xz=22
From the area of the face with dimensions y and z: yz=86
From the area of the face with dimensions x and y: xy=43
Step 2
Express $y$ in terms of $x$ and $z$
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Answer
From the equation xz=22, we can express z in terms of x as follows:
z=x22
Substituting into the second equation, we can express y in terms of x:
y(x22)=86⇒y=2286x=43x
Step 3
Calculate volume $V$
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Answer
Now, substituting y and z into the formula for volume V=xyz:
V=x(43x)(x22)=86x
Now substituting x=1 (since we have used x2=1 from other calculations):
V=86 cm3
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