The rectangle ABCD is shown below.
Calculate the area of the rectangle.
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The rectangle ABCD is shown below.
Calculate the area of the rectangle.
We will use the Pythagorean theorem in order to find the side DC:
We begin by inserting the existing data into the theorem:
Finally we extract the root:
168
Look at the rectangle below.
Side DC has a length of 1.5 cm and side AD has a length of 9.5 cm.
What is the perimeter of the rectangle?
The diagonal is the hypotenuse of a right triangle, not a side of the rectangle! Rectangle area requires length × width, which are the two perpendicular sides.
In a rectangle, the diagonal is always the longest side (hypotenuse). The two given measurements are the legs of the right triangle formed by the diagonal.
That's normal! Use a calculator to find . Some problems have perfect square roots, others don't. Keep all decimal places for accuracy.
No! This only works for rectangles because they have right angles. Other quadrilaterals don't form right triangles with their diagonals.
Compare your answer to simple estimates: if sides are about 7 and 24, the area should be around 7 × 24 = 168. This matches our exact answer!
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