Big Book Section 3 doubt


Hi guys, how would you solve this questions? I couldn’t find a suitable explanation anywhere. My process was considering two options for sides (8,8,2) OR (8,5,5). But I couldn’t figure out the next step.

Test cases

Pick each of the two cases

For triangle 8,5,5
Area = 1/2 bxh, here would = 1/2 x 8 x h = 4xh

Drawing this image out, the vertical line drawn to the vertex that divided the base of the isoceles triangle, give us two right triangles with sides= height h, 4 (base),5 (hypotenuse)

In this case, the height can only be 3 (3,4,5 right triangle)

Hence area = 4h = 4x3 = 12

For the second case

8,8,2

1/bxh = 1h

The right triangle formed would have a base = 1, hypotenuse = 8, height = h
Pythagorean theorem would give us a decimal for the height = 7.94
Area, bxh = 1x7.94 = 7.94

Hence, 12 is the answer

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