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The pyramid is shown in the diagram below.
The pyramid is built from four congruent triangles and one square as the base
We have the side of the square, so the area is = 10×10 = 100
We need the height of the triangle to work out its area. We can find out by using the height of the pyramid and half of the length of the side of the square.
Using the Pythagoras rule
Height of triangle =

Area of one triangle = 1/2×10×12=60
Surface area of the pyramid = 100 + (4×60) = 340 square inches
Y is equal to 21 and x is equal to 10
50) MAD=1.6
Follow steps...
<span>To find the mean absolute deviation of the data, start by finding the mean of the data set.
Find the sum of the data values, and divide the sum by the number of data values.
Find the absolute value of the difference between each data value and the mean: |data value – mean|.
Find the sum of the absolute values of the differences.
<span>Divide the sum of the absolute values of the differences by the number of data values.</span></span>