Answer:
56 units²
Step-by-step explanation:
Each triangle has an area that is ...
... A = 1/2bh = 1/2·7·4
There are 4 such triangles, so the total area is ...
... 4A = 4(1/2)·7·4 = 2·7·4 = 56 . . . . units²
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An area formula customarily used when the diagonals are pependicular to each other is that the area is half the product of their lengths.
... A = (1/2)d1·d2 = (1/2)·14·8 = 56
