The diagram shows rectangle STUV - Edexcel - GCSE Maths - Question 8 - 2022 - Paper 3
Question 8
The diagram shows rectangle STUV. TQU and SRV are straight lines. All measurements are in cm.
The area of trapezium QUVR is A cm²
Show that A = 2x² + 20x.
Worked Solution & Example Answer:The diagram shows rectangle STUV - Edexcel - GCSE Maths - Question 8 - 2022 - Paper 3
Step 1
Find the area of trapezium QUVR
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Answer
To find the area of trapezium QUVR, we first identify the lengths of the parallel sides. The top base QU measures 5 cm and the bottom base SR measures 3 + 2x = (2x + 3) cm. The height of the trapezium, which is the distance between the two parallel bases, is defined by length of SV (4 cm).
The formula for the area A of a trapezium is given by: A=21(b1+b2)⋅h
where b1 and b2 are the lengths of the parallel sides and h is the height.
Thus, we have:
A=21(5+(2x+3))⋅4
Substituting this into the formula yields: A=21(2x+8)⋅4=(x+4)⋅4=4x+16.
Step 2
Simplify the equation
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Answer
Next, we substitute the trapezium area calculated into the equation and we could add the areas of the triangles that make up QUVR:
A=Area of triangles+Arectangle
Adding the additional areas:
Area of triangle QTU
where height is 2x and base is the difference in lengths of SV and QU, yielding: AreaQTU=21(b⋅h)=21((4−2x)⋅(2x))=4x−2x2
Now adding the area of the rectangle STUV which is 12 cm² (width of 3 cm and length of 4 cm).
Thus via summation, we establish: