Question

find areas of shaded regiion
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Answer 1

$area \: of \: square = 21 \times 21 \\ \: \: \: = 441 {cm}^{2} \\ if \: we \: construct \: in \: the \: without \: shading \: diagram \: \\ the \: it \: has \: 4 \: circles \: and \: they \: are \: equal \: diameter . \\ \\ total \: line \: of \: without \: shading \: region = 21 - (6.5 + 6.5) \\ = 21 - 13.0 \\ = 8.0 \: cm \\ so \: \: diameter \: of \: a \: circle \: = 8 \div 2 = 4cm \\ rdius \: of \: a \: circle = 2cm \\ \\ without \: shading \: region \: make \: small \: square = 4 \times 4 \: \\ = 16 {cm}^{2} \\ area \: of \:4 semicircle \: = 4 \times \pi \times r \\ = 4 \times 3.14 \times 2 = 25.12 {cm}^{2} \\ area \: of \: shaded \: region \: = 441 - (25.12 + 16) \\ = 441 - 41.12 \\ = 399.88 {cm}^{2}$