Answers

2016-04-22T20:07:22+05:30
Sides of the banner
112 cm
78 cm
50 cm

So the semi perimeter = a + b + c /2
                                        =  112 + 78 + 50/2 = 120

Area by usind heron's formula

= √s(s-a)(s-b)(s-c)
= √ 120 (120-112)(120-78)(120-50)
=√120 × 8 × 42 × 70
= 1680 cm²

Area of 10 banners ( because 10 students are asked to make banner )
=1680 × 10 = 16800 cm²

Cost of banner = 3/100 × 16800
                            = Rs. 504
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