For the most part, the cross-section formed is a <em>trapezoid</em>, but if the slice passes through the apex of the pyramid, that shape is a <em>triangle</em>.
(Image source: MathCaptain.com)
(i) Note that it is given to you that 3a + 2b = 9
You are trying to find the value of 9a + 6b. Find what is multiplied to both the variable a & b. Divide:
(9a + 6b)/(3a + 2b) = 3
Next, multiply 3 to the 9 on the other side of the equation:
3 x 9 = 27
27 is the value of 9a + 6b.
(ii) Note that it is given to you that 8x + 6y = 60
You are trying to find the value of 4x + 3y. Find what is multiplied to both the variable x & y. Divide:
(8x + 6y)/(4x + 3y) = 2
Next, divide 2 from the 60 on the other side of the equation:
60/2 = 30
30 is the value of 4x + 3y.
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