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A trapezium has parallel sides of lengths 17 cm and 29 cm, and the distance between them is 15 cm. What is the area of the trapezium?
335 cm2
315 cm2
325 cm2
345 cm2
345 cm2
Use the average of the two parallel sides: Average=217+29тАЛ=23. Multiply this average by the distance: 23├Ч15=345.
Parallel sides (a) = 17 cm, (b) = 29 cm and distance (height) between them (h) = 15 cm.
Area=21тАЛ├Ч(a+b)├Чh
Use the average of the two parallel sides: Average=217+29тАЛ=23. Multiply this average by the distance: 23├Ч15=345.
Students often accidentally add the distance into the sum of the parallel sides or forget to divide by 2, leading to incorrect calculations.
Identify given values
Identify the length of parallel sides as a=17 cm and b=29 cm, and the height as h=15 cm.
a=17,b=29,h=15
Apply Area formula
Substitute the values into the standard area formula for a trapezium.
Area=21тАЛ├Ч(17+29)├Ч15
Simplify and Calculate
Calculate the sum inside the parentheses: 17+29=46. Then multiply by half of 46 (which is 23) and the height (15).
Area=21тАЛ├Ч46├Ч15=23├Ч15=345
D is correct because the calculated area using the trapezium formula is 345 cm2.
This formula is a specific case of the area of a polygon; remember that any shape with parallel bases follows the logic of Average Width ├Ч Height.