The right-angled triangle ABC is shown in the diagram below - Junior Cycle Mathematics - Question 13 - 2016
Question 13
The right-angled triangle ABC is shown in the diagram below. The square BDEC is placed on the hypotenuse of this triangle.
The area of the triangle ABC is 12a² squa... show full transcript
Worked Solution & Example Answer:The right-angled triangle ABC is shown in the diagram below - Junior Cycle Mathematics - Question 13 - 2016
Step 1
Step 1: Formula for the area of a triangle
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Answer
The area of a triangle is given by the formula:
Area=21×base×height
In this case, we have:
21×(6a)×∣AC∣=12a2
Step 2
Step 2: Finding |AC|
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Answer
Rearranging the equation from Step 1 gives:
∣AC∣=6a12a2×2=4a
Thus, the length of side |AC| is 4a units.
Step 3
Step 3: Substitution into Pythagoras' Theorem
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Answer
Using the Pythagorean theorem:
∣AB∣2=∣AC∣2+∣BC∣2
Substituting the known values gives us:
(6a)2=(4a)2+∣BC∣2
Solving this yields:
36a2=16a2+∣BC∣2∣BC∣2=36a2−16a2=20a2
Thus, |BC| = √(20a²) = 2√5a.
Step 4
Step 4: Finding the area of BDEC
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Answer
Now, the area of the square BDEC can be found as follows:
Area=∣BC∣2=(2√5a)2=4imes5imesa2=20a2
The area of square BDEC in terms of a² is thus 20a².
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