Step 1: Understand the problem

The problem is how much cardboard will Eric need if the base measures 20cm and the height 18cm?

Step 2: Devise a plan (translate)

My plan is to solve for the total surface area of the pyramid to achieve the answer.

Step 3: Carry out the plan (solve).

Given: height = 18 cm; base = 20 cm

Total Surface Area of a pyramid:

A = L + B = a2 + a√(a2 + 4h2))

A = a(a + √(a2 + 4h2))

A = 20(20+√(20²+4(18)²))

A = 1223.65 cm²

Step 4: Look back (check and interpret).

Please refer to the picture attached for more explanation.

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Contact me in my email if you want more help:

[email protected]

or in my messenger account: Dianne Lopez

Thank you.