In the diagram below, ABCD is a trapezium - OCR - GCSE Maths - Question 19 - 2017 - Paper 1
Question 19
In the diagram below, ABCD is a trapezium.
Length AE is 37.5cm.
DE = CF
Find the value of angle x.
A -------------- B
E
/|
/ |
D--C
| |
| ... show full transcript
Worked Solution & Example Answer:In the diagram below, ABCD is a trapezium - OCR - GCSE Maths - Question 19 - 2017 - Paper 1
Step 1
Find length DE or CF
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Answer
Using the trapezium properties, we see that triangles ADE and BCF are similar. Thus, we have:
DE=CF=62.5cm−37.5cm=25cm
Step 2
Set up sine relationship
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Answer
For triangle ADEF, we can use the sine ratio:
sin(x)=ADDE
Where AD is the hypotenuse.
Given AD is calculated using Pythagorean theorem:
AD=(62.52+(37.52))
Step 3
Calculate angle x
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Answer
Using inverse sine, we calculate:
x=sin−1(AD25)
Substituting the values for DE and AD gives the final angle measurement.